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MJ Jung

First World Problems

One of the most common writing tasks on intermediate-level German language exams is a formal letter of complaint.

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MJ Jung

Insatiable Desire in Tanz der Vampire

I have always preferred musicals that do not take their plots too seriously.

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MJ Jung

The Leaning Tower of Pisa

In the summer of 2018, I went to Pisa for the European Go Congress, partly as a participant and partly as a volunteer.

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Handy Picks

395 tools · 395 available

PDF Image Extractor

Extract the pictures inside a PDF. Preview them, then save individual PNGs or a ZIP in your browser.

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Crossword Puzzle Maker

Turn your own words and clues into a printable crossword and answer key.

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Sourdough Bulk Fermentation Chart

Compare measured dough volume with your recipe’s rise target, then copy or print a record of this batch.

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RPE Calculator

Enter a completed set to estimate the weight for your next set at a chosen number of reps and RPE.

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Gift Exchange Generator

Add names, draw gift partners, then print cards or copy a message for each person.

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Potluck Sign-up Sheet

See who is bringing what. Fill the slots, generate your sheet, then save it.

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Travel Packing List

Tell us about your trip. Get a packing checklist with quantities, then tick items as you pack.

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Customer journey map maker

Turn your own customer research or clearly marked assumptions into an editable, printable journey map.

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Classroom seating chart

Arrange a class roster in rows, pairs, or pods with fixed-seat and keep-apart rules.

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Meeting agenda maker

Build a timed agenda with owners, preparation, outcomes, and clear start and end times.

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Reading log maker

Design a blank printable log or fill in reading records before printing.

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Party planner

Edit preparation tasks, owners, deadlines, and the day-of running order.

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Label Maker

Turn names, addresses or product text into label sheets ready to print. Paste a list, import a CSV, or repeat one label.

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Ticket Maker

Create numbered tickets for your own event, with matching tear-off stubs and print-ready sheets.

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Round robin generator

Turn a team list into rounds, timed matches and a live standings table.

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Stencil maker

Make a stencil from text or a photo, add support bridges, then print it at your chosen size.

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PDF table to Excel

Extract tables from a local PDF, check the rows and columns, and save an editable Excel workbook. Your file stays in your browser.

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Moon phase calendar

Build a monthly calendar with daily illumination and the local times of the four main phases.

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Handwriting worksheets

A little practice, one letter, word or sentence at a time.

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Moving checklist

Turn your moving date into a practical timeline. Edit tasks, tick them off and keep your progress.

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Christmas card maker

Make it yours. Arrange photos, words and little festive details on your own Christmas card.

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Song BPM Finder

Find the approximate tempo of a song, compare half and double time, and copy the BPM. Your audio stays in your browser.

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Walking Calories Calculator

Estimate calories burned from your weight, walking time and speed on a firm, level surface.

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Ring Size Calculator

Convert ring measurements and compare eight sizing systems, including European circumference sizes and British letter sizes.

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GIF to video

Convert a local animated GIF into an MP4 video, with a solid background and a fixed number of repeats.

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STL viewer

Open a local STL model, rotate and zoom it, and inspect its triangles without uploading the file.

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Image to text

Read printed English or Korean from a local photo, then edit, copy or save the recognized text.

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Python Playground

Run Python in your browser with standard input, output and a stop button.

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Pigpen Cipher

Encode text as pigpen symbols, or use the symbol keypad to decode a message.

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Golf Handicap Calculator

Estimate a Handicap Index from 3–20 complete rounds, or convert an existing Index into a Course Handicap.

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Weird Object Gacha

Use free tickets to summon and collect 62 unusual everyday objects.

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Storyboard Creator

Arrange your images and scene notes into a storyboard you can print, save as PDF and reopen later.

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Banner Maker

Arrange text and your own background image, then download a PNG at the exact pixel size you choose.

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Video to audio

Extract the sound from a local MP4 or WebM video and save a WAV audio file.

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PDF splitter

Choose pages from a PDF and save them together, or as one PDF per page in a ZIP.

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Image grid splitter

Divide a JPG, PNG or WebP into rows and columns, then download all PNG tiles in a ZIP.

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HTML & CSS editor

Edit HTML and CSS, see a live preview, then copy or download the static HTML page.

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JSON tree editor

Paste or open JSON, edit its keys and values in a tree, then copy or save the updated JSON.

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Camping Checklist

Customize a short camping packing list with categories, quantities, and checkboxes. Print your current list or save it as PDF.

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Sudoku Solver

Enter a 9×9 Sudoku to check for mistakes and find whether it has one solution, several solutions, or no solution.

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Annual income calculator

Convert hourly, weekly, monthly or annual gross pay using your working hours and paid weeks.

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Caffeine half-life calculator

Estimate the caffeine left from today’s drinks.

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Word counter

Count words, Unicode characters and blank-line-separated paragraphs locally in your browser.

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YAML to JSON

Convert one YAML document to valid JSON locally with duplicate-key, tag, alias and unsafe-value checks.

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Subnet calculator

Calculate an IPv4 network, mask, address range, broadcast and usable hosts from IP/CIDR locally.

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Video to GIF

Trim a short MP4 or WebM clip and download a 480 px, 10 fps animated GIF.

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Audio Converter

Decode one local audio file and download a real MP3 or WAV without uploading it.

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HEIC to JPG

Convert one supported HEIC still photo into a previewed JPG without uploading it.

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Email signature generator

Enter your contact details, preview a simple email signature, then copy the formatted signature or its HTML.

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Word search maker

Turn your own word list into a printable word search and matching answer key, with diagonal and backward options.

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Webcam and microphone test

Preview a selected camera and watch the live input level from a selected microphone before a call.

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Gamepad tester

See the buttons and axes your browser receives from a connected game controller, including standard and raw mappings.

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Flowchart maker

Arrange shapes and arrows, then download your flowchart as SVG or PNG.

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Keyboard test

See which keyboard keys your browser receives, including simultaneous presses, left and right modifiers, repeat events and key codes.

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Exponential Regression Calculator

Fit y = a·exp(bx) to positive paired data by least squares on ln(y), then compare the observed points with the fitted curve.

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Waist-to-Height Ratio Calculator

Divide waist circumference by height in the same unit and read the result with NHS measurement limits.

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Macro Calculator

Convert a calorie target and your chosen carbohydrate, protein, and fat percentages into grams.

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Binomial Probability Calculator

Calculate exact, cumulative, tail, or interval probabilities and inspect the binomial distribution.

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Softball Bat Size Chart

Find a starting bat length by height and weight, with a brand-independent fastpitch reference and metric equivalents.

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Image to JPG

Convert a static PNG, WebP or JPEG into a real JPG file. Choose a solid background for transparency and compare the decoded original with the saved result.

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Black and white image converter

Turn a color photograph into grayscale, adjust its contrast and download a PNG. Compare the original and generated result before saving.

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Cursive text image generator

Create actual handwriting artwork with Dancing Script, Caveat or Pacifico. Download a transparent PNG or an SVG made of outlines.

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Mind map maker

Organize a central idea into branches. Edit text directly, drag topics to move or reconnect them, choose colors and download the map.

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Matrix diagonalization calculator

Find P, D and P⁻¹ for a real 2×2 matrix, then check A = PDP⁻¹.

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Dilution calculator

Make a weaker solution: enter the strength you have, the strength you want, and how much finished solution you need.

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US storage unit size guide

See how many moving boxes or common furniture items fit in a simple layout using US self-storage sizes.

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PDF to image converter

Render selected PDF pages as PNG or JPEG images locally in your browser, with page ranges and downloadable previews.

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PDF to text converter

Extract the existing text layer from selected PDF pages locally, review it by page, copy it, or download a TXT file.

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Crop PDF pages

Draw a crop area on a PDF preview and apply it to the current page or all pages, locally in your browser.

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Image to PDF Converter

Turn ordered JPG and PNG photos into one downloadable PDF in your browser.

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Image Compressor

Compare the original with a smaller JPG or WebP and download the actual result.

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Printable Calendar Maker

Create a monthly or yearly calendar and download a portrait or landscape A4 or Letter PDF.

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Printable chore chart maker

Edit people, chores and assignments, preview a weekly chart, then print or save it as an A4 or US Letter PDF.

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Home maintenance checklist maker

Choose, edit, add, and remove home observation or professional-service items, then print an A4 or Letter checklist.

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Aquarium maintenance checklist maker

Edit a freshwater aquarium observation, equipment, cleaning, and record checklist, then print or save it as A4 or Letter PDF.

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Seasonal color palette

Choose a season and explore an original clothing color reference. Copy HEX codes and save a three-color outfit combination.

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Garden layout planner

Lay out beds, crop areas and paths on a measured 2D grid. Name each area and save your garden plan.

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Room layout planner

Arrange furniture to scale in a simple 2D room. Edit dimensions, move and rotate pieces, then save your plan.

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Exercise Intensity Classifier

Classify relative effort or speaking ability using CDC intensity references.

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AFT Score Calculator

Convert five AFT event results into points using the selected profile and official scoring tables.

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Body Fat Calculator

Estimate body fat percentage from height and tape measurements using the historical circumference equations.

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Protein Intake Calculator

Convert the adult protein RDA or the athlete reference range into grams per day from your body weight.

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Golf Swing Weight Calculator

Estimate a golf club’s Lorythmic swing-weight code from its total assembled mass and measured balance point.

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Online Scoreboard

Keep two team names, scores, and a drift-resistant countdown timer on one clear board, with touch, keyboard, and full-screen controls.

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Dog Age Calculator

Compare your dog’s age with human years using a size-based reference chart.

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Cat Age Calculator

Convert your cat’s age to an approximate human age and see its feline life stage.

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Baseball Glove Size Chart

Find a reference glove length by age and position, and see how to measure the glove.

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Helmet Size Chart

Measure your head and compare general cycling and snow helmet size ranges.

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Roofing calculator

Estimate the surface area of a simple roof and the number of material packs from your dimensions, slope and coverage.

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Aquarium calculator

Calculate water volume and freshwater weight from internal tank dimensions and the actual fill height.

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Steps to Miles Calculator

Turn a step count and your measured step length into miles and kilometers.

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Bike Size Chart

Read road, mountain and kids’ bike size tables. Optionally highlight the rows matching your height.

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Baseball Bat Size Chart

Find a starting bat length in a height-and-weight table. Read the chart directly or highlight your range.

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MLA Citation Generator

Create MLA 9 citations from book, journal article or webpage information. Paste a source or a list, review the fields, then copy the finished text.

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CSE Citation Generator

Create CSE 9 · Citation–sequence citations from book, journal article or webpage information. Paste a source or a list, review the fields, then copy the finished text.

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Harvard Citation Generator

Create Leeds Harvard citations from book, journal article or webpage information. Paste a source or a list, review the fields, then copy the finished text.

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Vancouver Citation Generator

Create Vancouver · NLM / ICMJE citations from book, journal article or webpage information. Paste a source or a list, review the fields, then copy the finished text.

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Screen test

Show solid white, black, red, green, blue and gray screens to inspect pixels, marks and uneven areas by eye.

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Touch screen test

Draw touch trails, cover a grid and view simultaneous contacts to check the touch events your browser receives.

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AMA Citation Generator

Create AMA 11 citations from book, journal article or webpage information. Paste a source or a list, review the fields, then copy the finished text.

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Chicago Citation Generator

Create Chicago 18 citations from book, journal article or webpage information. Paste a source or a list, review the fields, then copy the finished text.

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IEEE Citation Generator

Create IEEE · 2023 citations from book, journal article or webpage information. Paste a source or a list, review the fields, then copy the finished text.

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ACS Citation Generator

Create ACS Guide · 2026 citations from book, journal article or webpage information. Paste a source or a list, review the fields, then copy the finished text.

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Turabian Citation Generator

Create Turabian 9 citations from book, journal article or webpage information. Paste a source or a list, review the fields, then copy the finished text.

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Hat Size Converter

Compare head circumference with US, UK and metric hat sizing.

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Belt Size Calculator

Find belt size labels from your measured waist or trouser size, and estimate trouser waist from a belt label.

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Glove Size Calculator

Compare hand circumference with traditional inch-based glove sizes.

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Shoe Size Converter

Find US, UK, EU, JP/CM and BR shoe sizes in a named adult size chart, with separate men's and women's footwear references.

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Bra Size Calculator

Measure underbust and bust to find a starting size in the Triumph chart, with EU, UK, US and French labels.

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Race time predictor

Estimate a finish time at another distance from a recent race, and compare 5K, 10K, half marathon and marathon times.

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Waist-to-hip ratio calculator

Divide waist circumference by hip circumference, with clear measuring positions and centimetre or inch inputs.

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Image metadata remover

Inspect one JPEG or PNG, create a separately downloaded copy without supported EXIF, GPS, XMP, IPTC or comment metadata, and verify the new file before download.

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Ski Size Calculator

Estimate an adult piste ski length from height and ability.

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Snowboard Size Calculator

Estimate a snowboard starting length from height and riding style; check your weight against the chosen model.

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Golf Club Length Calculator

Estimate a 5–9 iron length using wrist-to-floor measurement and a stated baseline.

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Word Unscrambler

Use this word unscrambler to find English words from some or all of your letters. Browse every match by length, longest first. Each letter can only be used as often as entered.

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Crossword Word Finder

Enter known letters and one _ for each missing letter. Match exactly 2–15 positions, with at least one known letter.

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Anagram Solver

Use every letter exactly once per occurrence. Find single words with exactly the same letters and counts.

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Markdown editor

Write plain Markdown on the left and read a safe live preview on the right. Copy or save the original source when it is ready.

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Batting average calculator

Enter hits and official at-bats to calculate a baseball batting average in the familiar .300 format.

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Bowling score calculator

Enter pins for each roll and calculate a familiar 10-frame scorecard. Frames stay unconfirmed until their bonus rolls are known.

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Dunk Calculator

Find the vertical jump needed for your chosen dunk height using measured standing reach, rim height and clearance.

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Swim Time Converter

Estimate SCY, SCM and LCM event times using the published NCAA Division II 2023–24 conversion factors.

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Bench Press 1RM Calculator

Estimate your bench press one-rep max with the Brzycki formula and view a 50–100% load table.

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Powerlifting Score Calculator

Compare DOTS and original Wilks points from your bodyweight and three-lift total in kg or lb.

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UPC barcode generator

Enter 11 UPC-A digits to calculate the check digit, or all 12 digits to validate it, then download the barcode as SVG or PNG.

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Image to PNG converter

Convert one static JPEG, WebP or PNG image into a PNG file while keeping its decoded dimensions, aspect ratio and transparency.

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Printable Habit Tracker

Enter up to 12 habit labels and choose a month to create one clean, blank monthly grid for printing. Nothing is checked or tracked online.

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ASCII Art Generator

Choose a static image and convert its brightness into fixed-width characters. Preview, copy, or save the exact text while the image stays in your browser.

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Password Generator

Create one random password in your browser. Choose its length and required character types, then copy it without saving or sending it anywhere.

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Tree Diagram Maker

Turn an indented list into a clear hierarchy. Preview your tree and download the full diagram as PNG or SVG.

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APA Citation Generator

Enter the author, title and publication details. Get an APA 7 citation to copy into your document.

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Online screen recorder

Record a short screen, window or browser-tab video, preview it and save the file locally. No installation or account required.

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Pixel Art Maker

Draw pixel art with a pen and eraser, then save a transparent PNG.

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Sprite Sheet Maker

Combine sprite images you already have into one PNG sheet. Draw the original artwork in Pixel Art Maker first.

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LaTeX Table Generator

Edit cells or paste TSV to create escaped LaTeX tabular code.

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Quiz Maker

Write a quiz, then print question sheets and answer keys or save them as PDF.

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Sitemap Generator

Paste your website URLs to create an XML sitemap file in your browser.

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Favicon Generator

Turn one PNG, JPEG or WebP image into ICO and PNG website icons.

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Invitation Maker

Make a personal invitation with your event details and an optional photo. Preview, download a PNG, or print a 5 × 7 inch card.

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Timeline Maker

Arrange up to 40 events by date or time. Copy or save text, Markdown and PNG, with a live A4 print preview.

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Invoice Generator

Enter the parties, charges, discount and tax rate to create a clear printable invoice. Currency changes the displayed symbol only; it does not convert values.

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Class Schedule Maker

Add up to 40 classes to build a printable Monday–Sunday timetable. Overlapping classes are marked so you can fix them before printing.

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Online teleprompter

Paste a script and read it with adjustable automatic scrolling, type size, fullscreen and keyboard controls.

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Online voice recorder

Record microphone audio in your browser, pause or resume, preview it and download the format your browser actually created.

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Word cloud generator

Turn text or word counts into a readable word cloud and download a PNG.

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Photo contact sheet maker

Create printable photo pages with thumbnails and filenames.

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Absolute Value Calculator

Solve |ax + b| compared with c and see the solution on a number line.

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Quadratic Inequality Calculator

Find where ax² + bx + c is positive or negative, including linear and constant cases.

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Vector Projection Calculator

Project a 2D or 3D vector onto a direction and check the perpendicular remainder.

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Inverse Matrix Calculator

Invert a 2 × 2 or 3 × 3 numerical matrix and inspect its identity product.

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Sample size calculator

Estimate the responses needed to measure a population proportion.

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Effect size calculator

Calculate signed Cohen's d and approximate Hedges' g for two independent groups.

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Shannon entropy calculator

Turn category counts or probabilities into entropy in bits and per-category contributions.

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Geometric and harmonic mean calculator

Compare weighted or unweighted geometric, harmonic and arithmetic means for positive values.

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Polish notation converter

Convert arithmetic between infix, prefix and postfix notation, with a readable evaluation stack.

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RREF and rank calculator

Reduce a small matrix to reduced row echelon form using exact fractions and visible row operations.

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Symmetric 2×2 eigenvalue calculator

Find two real eigenvalues, unit eigenvectors and their directions for a symmetric 2×2 matrix.

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PLU decomposition calculator

Factor a 2×2 or 3×3 matrix using partial pivoting and check P·A = L·U.

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Partial fraction calculator

Decompose a proper rational fraction with two to four distinct linear factors and verify the exact coefficients.

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Rational root calculator

List rational-root candidates and test which ones are exact roots of a small integer-coefficient polynomial.

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Chinese remainder calculator

Find the smallest total that matches the remainders from different group sizes.

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Modular exponentiation calculator

Find the exact remainder of an integer power, including negative bases.

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JSON Formatter

Format, minify and validate JSON locally while preserving number lexemes, string escapes, key order and duplicate keys.

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XML to JSON

Convert pasted XML to an explicit JSON tree that preserves element names, attributes, text order, repeated elements and namespaces.

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CSV to JSON

Convert pasted CSV to a JSON array with delimiter and header controls while preserving every cell as a string.

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Hash Generator

Generate SHA-256, SHA-384 or SHA-512 hexadecimal digests from UTF-8 text locally with the Web Crypto API.

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Email Extractor

Extract email-like addresses from user-provided text, one per line, with duplicate removal and lowercase options.

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Quaternion calculator

Multiply, conjugate, invert or normalize a quaternion, or rotate a 3D vector.

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Interval notation converter

Convert a simple inequality to an interval, or an interval to an inequality, with a number line.

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Time zone converter

Compare the same instant in two IANA time zones, including date changes and UTC offsets.

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Color palette generator

Generate 3–8 colors, preserve favorites, edit HEX values and export your palette.

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Music Scale Calculator

Find major and natural minor scale notes, key signatures and relative keys, with a semitone diagram.

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Fret Position Calculator

Calculate equal-tempered fret distances from the nut and adjacent fret spacing, with a proportional string diagram.

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Harmonic Series Calculator

List integer-multiple harmonic frequencies and compare each with the nearest equal-tempered note and cents offset.

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Uniform Distribution Calculator

Calculate continuous uniform density, cumulative probability and interval probability, with the exact overlap area highlighted.

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Aspect ratio calculator

Keep an image’s proportions when planning a new width or height.

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PPI calculator

Find pixel density, pixel pitch and physical display dimensions.

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Print size calculator

Convert image pixels into print dimensions, or plan the pixels a print needs.

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Reverb time calculator

Plan a tempo-based pre-delay and decay pair in milliseconds.

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Time card calculator

Paint your working hours on a 24-hour timetable. Keep a local draft and export totals.

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Baking cost calculator

Calculate ingredient usage, labor, other costs, batch total and cost per baked item with compatible unit conversion.

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Hamming code calculator

Encode and check Hamming(7,4) or Hamming(15,11) codewords with even parity and single-bit correction steps.

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Base64 encoder & decoder

Encode UTF-8 text to Base64 or Base64url and decode valid Base64 back to UTF-8 text in your browser.

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URL encoder & decoder

Percent-encode or decode Unicode URL components and complete URIs without visiting or sending the input.

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UUID v4 generator

Generate 1 to 100 UUID version 4 identifiers with the browser cryptographic random generator.

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Case converter

Convert plain text between locale-aware uppercase, lowercase, sentence case, and simple title case while preserving whitespace.

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Reverse text

Reverse plain text by Unicode grapheme cluster, preserving joined emoji and combining marks, with an exact double-reversal check.

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Unicode text styler

Map supported ASCII letters and digits to copyable Mathematical Alphanumeric Unicode symbols while preserving unsupported characters.

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ASCII code converter

Convert 7-bit ASCII text to binary, decimal, or hexadecimal codes and decode validated 0–127 code sequences.

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Truth table generator

Parse Boolean expressions with up to six variables and generate ordered truth tables for NOT, AND, XOR, OR, implication, and equivalence.

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Box Plot Calculator

Turn a number list into quartiles, whiskers and outliers with a matching box plot.

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Dot Plot Calculator

Count repeated values and draw every observation on a numerical dot plot.

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Hypergeometric Distribution Calculator

Calculate exact and cumulative probabilities for random sampling without replacement.

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Cubic Equation Calculator

Find the real and complex roots of ax³ + bx² + cx + d = 0 and see the real roots on a graph.

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Fraction calculator

Add, subtract, multiply or divide two fractions with exact reduced answers and a number line.

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Fraction simplifier

Reduce a fraction, see its mixed form and understand why its value stays the same.

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Fraction comparison calculator

Compare two fractions exactly using cross-products and a shared number line.

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Complex number calculator

Calculate with a + bi and c + di, including conjugation, and plot the result.

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Complex polar converter

Convert a complex number between a + bi, polar and exponential notation with an angle diagram.

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eDPI Calculator

Multiply mouse DPI by in-game sensitivity, then optionally keep that eDPI when changing DPI in the same game.

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Pizza Size and Price Calculator

Compare two circular pizza orders by total area and price per square unit—not diameter alone.

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Floating-Point Converter

Encode a number as IEEE 754 float32/64, or decode an exact binary or hexadecimal bit pattern.

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Point to plane distance calculator

Find the shortest distance from a 3D point to a plane, and the exact location where its perpendicular meets the plane.

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Plane equation calculator

Build a plane from a point and its normal, or from three points, and see how the points and perpendicular direction define it.

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Sphere equation calculator

Convert a center and radius into sphere equations, or recover the center and radius from expanded numerical coefficients.

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Irregular polygon area calculator

Calculate the area and perimeter of a polygon from its ordered 2D vertices, with a drawing of the boundary you entered.

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Modular inverse calculator

Solve a × x ≡ 1 (mod m) for the least non-negative integer x, or see why no inverse exists.

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Expected value calculator

Add each outcome and its probability to calculate Σxᵢpᵢ without silently normalizing the probabilities.

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System of linear equations calculator

Enter coefficients for two or three equations, classify the system, and verify a unique solution by substitution residual.

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Atbash cipher decoder and encoder

Translate a short puzzle message with the fixed reversed alphabet: A becomes Z, B becomes Y, and the same operation decodes the result.

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Caesar cipher decoder and shift encoder

Move each English letter by a chosen whole-number shift. Encode adds the shift, Decode subtracts it, and shift 13 provides ROT13.

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Vigenère cipher decoder and encoder

Apply a repeating English keyword as a different Caesar shift for each A–Z letter, with explicit Encode and Decode directions.

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Substitution cipher decoder and encoder with key

Provide all 26 replacement letters once, then encode with the mapping or decode through its exact inverse. This tool never guesses a missing key.

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Baker's Percentage Calculator

Convert flour-based percentages and ingredient weights, including the flour and water inside a starter.

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Coffee Ratio Calculator

Calculate brew water from coffee mass, or coffee mass from brew water, using a custom 1:X ratio by weight.

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RAID capacity calculator

Compare raw, usable and redundancy capacity for one equal-size-drive RAID array.

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Uptime and downtime calculator

Calculate allowed downtime from an uptime target, or measured uptime from a known outage total.

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Poisson Distribution Calculator

Find the probability of an event count from its average rate, with exact and cumulative probabilities and a bar chart.

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Exponential Distribution Calculator

Calculate waiting-time probabilities or find a time from a cumulative probability, with the selected area under the density curve.

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Geometric Distribution Calculator

Find the probability of the first success on or before a trial, using a fixed success probability and a matching bar chart.

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Color Contrast Checker

Compare a text color with its background and check the four WCAG 2.2 text contrast thresholds.

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CSS Gradient Generator

Arrange two to four color stops, preview the result, and copy the same CSS background value.

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CSS Box Shadow Generator

Set one box shadow, preview it on a test box, and copy the matching CSS declaration.

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Frequency table calculator

Turn a list of values into a readable frequency, relative-frequency, and cumulative-frequency table.

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Stem-and-leaf plot maker

Keep every observation visible while arranging a small dataset into ordered stems and leaves.

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3D Printing Cost Calculator

Estimate the direct cost of one print from the material used, print time, electricity and optional time charges.

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Takt Time Calculator

Turn available production time and required quantity for one period into a clear target pace.

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DPMO Calculator

Normalize counted defects by the number of inspected units and equal defect opportunities in each unit.

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Video timecode converter

Convert a zero-based frame number to timecode, or timecode back to its exact frame number.

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RAM latency calculator

Convert DDR data rate and CAS cycles into theoretical first-word CAS latency in nanoseconds.

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Bandwidth-delay product calculator

Calculate how much data can be in flight from link bandwidth and round-trip time (RTT).

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Correlation and covariance calculator

Calculate Pearson correlation and sample or population covariance for two paired lists, with a scatter plot.

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Simple linear regression calculator

Fit a least-squares line to paired X and Y values. See slope, intercept, R², predictions and residuals.

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Prediction error calculator

Compare actual and predicted values with SSE, MSE, RMSE and MAE, plus a signed error plot.

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Long addition calculator

Add two whole numbers and follow each carry.

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Long subtraction calculator

Subtract two whole numbers and see every regrouping across zeros.

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Long multiplication calculator

Multiply two whole numbers and follow carries, partial products and their sum.

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Set Operations Calculator

Compare two comma-separated sets with exact, case-sensitive text matching.

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Power Set Calculator

List the complete power set and verify its 2ⁿ cardinality.

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BPM and note duration calculator

Find a note’s duration while keeping the BPM beat unit explicit.

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Music duration calculator

Estimate a fixed-tempo passage from measures, meter, and an explicit BPM beat unit.

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Note name and frequency calculator

Convert a note or frequency with 12-tone equal temperament and your own A4 reference.

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Music transposition calculator

Measure chromatic semitone distance or move a note by a signed number of semitones.

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Polynomial calculator

Add, subtract, or multiply two one-variable polynomials from descending coefficient lists up to degree 10, with the interpreted expressions shown.

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Binomial expansion calculator

Expand (ax + b)^n for whole-number exponents from 0 to 20, with exact signs, powers, and descending coefficients.

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Typing speed calculator

Convert a known keystroke count and elapsed time into KPM, KPH, and five-keystroke GWAM.

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Data usage calculator

Add up to five activities using your own hourly data rate and duration.

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Amdahl's law calculator

Estimate ideal fixed-workload parallel speedup, efficiency, and runtime.

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Gear ratio calculator

Calculate one to three gear stages from tooth counts and input RPM, with a connected diagram and optional wheel speed.

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Pulley & belt calculator

Calculate output RPM and the geometric length of an open belt from pulley diameters and center distance.

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Camera field of view calculator

Calculate horizontal, vertical and diagonal angles and the field size from your sensor, actual focal length and distance.

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Crop factor calculator

Compare sensor sizes and calculate crop factor and a 35 mm equivalent focal length with a scaled sensor diagram.

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Depth of field calculator

Estimate near and far focus limits, total depth of field and hyperfocal distance using your circle of confusion.

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Exposure calculator

Compare ISO, aperture and shutter settings, or solve one target setting for the same exposure or a chosen stop difference.

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Ohm’s law calculator

Find voltage, current, resistance and power for one ideal DC resistor from two known quantities.

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Series and parallel resistor calculator

Calculate the equivalent resistance of 2–10 resistors connected entirely in series or entirely in parallel.

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SMD resistor code calculator

Decode common 3-digit, 4-digit and R-marked SMD resistor codes into ohms, kilohms and megohms.

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LED resistor calculator

Calculate the ideal series resistor and its power dissipation for a single LED at your chosen current.

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Trigonometric functions calculator

Calculate sin, cos, tan or the principal inverse angle in degrees or radians.

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Complementary and supplementary angle calculator

Find the angle that completes 90° and the angle that completes 180°.

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Law of cosines calculator

Solve the opposite side from SAS or a selected angle from three valid sides (SSS).

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Law of sines calculator

Solve a triangle from two angles and one opposite side, or list every valid SSA solution.

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Probability Calculator for Two Events

Enter two event probabilities and their known intersection to calculate the union and complementary regions.

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Conditional Probability Calculator

Find the probability of A after restricting the sample space to outcomes where B occurred.

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Bayes' Theorem Calculator

Update a prior probability after observing B in a two-case model: A or not A.

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Confusion Matrix Metrics Calculator

Check five binary-classification metrics from true and false positive and negative counts.

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Dice probability calculator

Find the probability that identical fair dice total exactly, at most, or at least your target sum.

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Coin flip probability calculator

Find the exact binomial probability of getting exactly, at most, or at least a chosen number of heads.

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Square pyramid calculator

Use the square base side and perpendicular height to find the volume, lateral area, total surface area and face slant height.

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Right triangular prism calculator

Enter all three sides of the triangular base and the perpendicular prism height to calculate volume and total surface area.

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Ellipsoid calculator

Enter the three semi-axes to find exact volume and an approximate surface area using the Knud Thomsen formula.

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3D coordinate converter

Convert between Cartesian, cylindrical and spherical coordinates with degree angles.

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Triangle calculator

Solve one valid triangle from its three side lengths (SSS).

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Regular polygon calculator

Find the main measurements of an equilateral, equiangular regular polygon.

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Arc and sector calculator

Calculate a circular arc, sector area and endpoint chord from radius and central angle.

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Projector screen calculator

Relate projector throw ratio, lens-to-screen distance and image dimensions without a model-specific preset.

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Time unit converter

Convert seconds, minutes, hours, days, and weeks, or change between decimal hours and hours-minutes-seconds.

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Time duration calculator

Add, subtract, or multiply time lengths without dates, clock times, or time zones.

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12-hour and 24-hour time converter

Convert a clock display in either direction. Dates and time zones are not involved.

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Speaking time calculator

Estimate presentation length from words and your chosen pace, or work backward from a target time.

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Electricity cost calculator

Estimate electricity use and cost from appliance power, running time and your electricity rate.

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Fuel cost calculator

Estimate fuel needed, total trip cost and cost per person from distance, fuel economy and your fuel price.

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Bath vs shower water usage

Compare bath and shower water use from bath volume, shower flow, duration and frequency.

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Meeting time and cost calculator

Estimate total person-hours and meeting cost from attendees, duration and a shared hourly rate.

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Roll length calculator

Estimate how much uniformly wound material remains without unrolling it.

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Tablecloth size calculator

Turn tabletop measurements and a chosen drop into finished cloth and cut dimensions.

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Curtain size calculator

Plan finished coverage and flat panel dimensions before cutting or ordering.

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Cross-stitch size calculator

Convert chart stitches into design dimensions and a fabric cut with margins.

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Integer calculator

Calculate with signed whole numbers exactly, including integer division with a quotient and remainder.

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Divisor calculator

Find the sorted positive divisors of one integer, together with their count and exact sum.

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Perfect square and cube checker

Test one signed integer for exact square and cube roots without approximating a general root.

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Place value calculator

Read every digit, its base-10 position and place value in a clear table, with an exact digit sum.

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Date calculator

Count days between two dates, or move a calendar date by years, months, weeks, and days.

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Leap year calculator

Check a Gregorian year and see whether it contains 365 or 366 days.

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Day of year calculator

Convert a date to its numbered day of the year, or turn a day number back into a date.

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Age calculator

Find chronological age on a chosen date and count the days until the next birthday.

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Render time calculator

Estimate an animation render from one measured frame, the total frame count, and the number of equal-performance machines.

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Time-lapse calculator

Plan how many photos you will capture and how long the finished video will be—or work backward from a target clip.

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Linear interpolation calculator

Estimate y at a target x from two known points on a straight line.

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Bilinear interpolation calculator

Estimate a value inside an axis-aligned rectangle from its four corner values.

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Video & audio file size calculator

Estimate data size from a total bitrate and playback time—no upload, codec guess, or conversion.

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Uncompressed image file size calculator

Calculate raw raster pixel data from dimensions and bits per pixel—without uploading an image.

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Matrix Addition, Subtraction & Scalar Multiplication

Apply an entry-by-entry operation to matrices up to 3 × 3.

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Matrix Multiplication Calculator

Multiply A × B by pairing each row of A with each column of B.

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Matrix Transpose Calculator

Turn rows into columns and columns into rows for a matrix up to 3 × 3.

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Speed calculator

Find your average running speed from distance and elapsed time, shown in the speed unit you choose.

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Pace calculator

Find how many minutes each kilometre or mile took from your running distance and total time.

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Line intersection calculator

Enter two standard-form lines to find their relationship and, when unique, their intersection point.

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Polar coordinate converter

Convert a 2D point both ways between Cartesian (x, y) and polar (r, θ) coordinates.

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Coordinate rotation calculator

Rotate a single 2D point around the origin with a positive counterclockwise angle.

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Cylinder calculator

Enter the radius and perpendicular height of a right circular cylinder to find volume, curved side area, and total surface area.

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Cone calculator

Enter the base radius and perpendicular height of a right circular cone to find slant height, volume, curved area, and total surface area.

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Matrix Determinant Calculator

Calculate det(A) for a 2 × 2 or 3 × 3 numeric matrix.

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Dot Product Calculator

Enter two 2D or 3D vectors to find their scalar dot product and the angle between their directions.

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Cross Product Calculator

Enter two 3D vectors to calculate A × B and the magnitude of the perpendicular result.

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3D Vector Direction Angle Calculator

Enter one nonzero 3D vector to find its three axis direction angles and direction cosines.

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Distance formula calculator

Enter two points to find their straight-line distance in a 2D coordinate plane.

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Section point calculator

Find an internal division point, or recover an endpoint when a midpoint is known.

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Line equation calculator

Write the equation of a straight line from two points or from one point and its slope.

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Cuboid calculator

Use three perpendicular edge lengths to find a rectangular box’s volume, total surface area and space diagonal.

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Sphere calculator

Start with a radius or diameter and find a sphere’s surface area, volume and matching dimension.

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Permutation Calculator

Count ordered selections from n available items when order matters, with or without repetition.

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Combination Calculator

Count selections from n available item types when order does not matter, with or without repetition.

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Rectangle calculator

Enter the length and width to find area, perimeter, and corner-to-corner diagonal.

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Circle calculator

Choose radius or diameter, enter one measurement, and calculate the circle’s key dimensions.

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Prime factorization calculator

Test one positive integer and write it as an exact product of prime factors.

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GCD and LCM calculator

Find the greatest common divisor, least common multiple, and collective coprime status for 2 to 20 integers.

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Power calculator

Enter a base and exponent to calculate aᵇ, including decimal and negative exponents when the result is a real number.

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Nth root calculator

Enter a number and an integer root degree to calculate ⁿ√x, including real odd roots of negative numbers.

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Logarithm calculator

Choose base 10, base e, or a custom base, then enter a positive number to find its logarithm.

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Arithmetic sequence — The nth term (aₙ)

The same number is added to each term. Find the nth term aₙ.

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Arithmetic sequence — The sum of the first n terms (Sₙ)

The same number is added to each term. Find the sum Sₙ of the first n terms.

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Geometric sequence — The nth term (aₙ)

Each term is multiplied by the same number. Find the nth term aₙ.

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Geometric sequence — The sum of the first n terms (Sₙ)

Each term is multiplied by the same number. Find the sum Sₙ of the first n terms.

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Consecutive integer sum

Add every whole number between two endpoints. Find the sum S of all consecutive integers from a through b, including both endpoints.

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Inverse proportion calculator

Find the missing value in an inverse proportion such as 4 × 10 = 8 × ?.

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Proportion calculator

Solve the missing value in a proportion such as 1 : 5 = ? : 10.

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Color code converter

Convert HEX, RGB, and HSL color codes and copy the result.

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Linear equation calculator

Solve ax + b = 0 and see the solution steps.

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Quadratic equation calculator

Find real roots, the discriminant, and vertex of a quadratic equation.

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Unix time converter

Convert Unix timestamps in seconds or milliseconds to UTC dates and back.

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Rounding calculator

Round numbers to decimal places, whole-number places, or significant figures.

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Length converter

Convert metric and imperial lengths, including feet and inches and fractional inches.

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Percentage calculator

Calculate percentages, increases, differences, percentage points, errors, and progress.

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Data unit converter

Convert data sizes and transfer rates between bits, bytes, decimal units, and binary units.

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Mass converter

Convert mass between grams, kilograms, tonnes, pounds, ounces, and stone.

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Scale calculator

Calculate actual length, drawing length, or the scale ratio from the other two values.

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Unit price calculator

Compare package prices and quantities to find the lowest price per unit.

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Number base converter

Convert whole numbers between binary, octal, decimal, and hexadecimal.

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Angle converter

Convert degrees, radians, arcminutes, arcseconds, and degrees-minutes-seconds.

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Paper weight & thickness

Calculate paper weight from sheet size and gsm, or thickness from a measured stack.

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Volume converter

Convert volume between liters, milliliters, and metric or imperial cubic units.

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Area converter

Convert area between metric, imperial, acre, and hectare units.

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CSS font unit converter

Convert CSS font sizes between px, em, pt, and % with a reference size.

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Temperature converter

Convert temperatures between Celsius, Fahrenheit, and Kelvin.

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Roman numeral converter

Convert whole numbers and standard Roman numerals in either direction.

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Markdown table generator

Paste cells, edit and sort, then copy a Markdown table.

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Paint calculator

Estimate paint volume and whole cans for walls and ceilings.

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HTML to Markdown

Convert HTML to Markdown with tables, lists, and code.

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Tile calculator

Estimate tile quantities, whole boxes, and material cost.

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Decimal to fraction

Convert finite or repeating decimals to exact fractions.

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SQL formatter

Format SQL with dialect, indentation, and keyword case options.

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Landscape material calculator

Estimate gravel or mulch quantities, packages, and cost.

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Screen size calculator

Compare screen dimensions, areas, and proportional outlines.

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Stair calculator

Calculate stair dimensions and see a proportional side view.

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Wallpaper roll calculator

Estimate wallpaper rolls, including pattern matching and trimming.

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Test grade calculator

Calculate test scores and print a grading chart.

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Flashcard maker

Create, flip and print your own study cards.

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Numbers to words

Write numbers and money amounts in six languages.

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Fabric calculator

Arrange rectangular pieces and estimate the fabric length you need.

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Polynomial division

Divide two polynomials. Get an exact quotient, remainder, and every step.

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Concrete calculator

Estimate concrete volume and bags for your project.

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Standard deviation calculator

Calculate sample and population standard deviation from your data.

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Morse code translator

Convert text and Morse code, then play the signals.

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Scientific notation calculator

Convert and calculate with scientific notation.

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Text compare

Compare two texts and highlight their differences.

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QR code generator

Turn a link or text into a downloadable QR code.

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Capybara Pond

Relax by a 3D pond with capybaras.

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Weighted grade calculator

Calculate your grade from scores and percentage weights.

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Final grade calculator

Find the final exam score needed for your target grade.

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Merge PDF

Combine PDF files in your chosen order.

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Long division calculator

See long division steps, the quotient, and the remainder.

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Cake pan size converter

Compare cake pan sizes and find the ingredient multiplier for the pans you have.

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Meal planner & grocery list

Plan meals, combine matching ingredients, and print a grocery list that stays in sync.

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Recipe scaler

Scale ingredients by servings or a multiplier, compare exact fractions, and print.

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Camping gear weight calculator

Add your gear, calculate category totals, and compare your pack against a baseline.

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Gantt chart maker

Turn task names and dates into a simple schedule, then print or save a PDF.

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Chart maker

Create bar or pie charts from your numbers, download a PNG, or print.

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Chord charts

Explore guitar, piano and ukulele chords. Arrange and print your practice sheet.

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Bingo cards

Make and print bingo cards with your own words or numbers.

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Seating charts

Import guests, arrange tables and seats, and print your event plan.

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Spelling worksheets

Turn your English word list into spelling practice.

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Certificates

Make fun awards and thoughtful thank-you certificates.

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Tournament brackets

Create, edit, and print a single-elimination bracket for 2–16 participants.

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