How to use this time-lapse calculator
- Choose “From shooting time” when you know how long the event or setup can run. Enter that real-world duration, the time between scheduled photos, and the playback fps.
- Choose “From target video” when you know the clip length you want. Enter the target length, capture interval, and fps; the calculator rounds the required photo count up to a whole photo.
- Read the photo count, finished clip length, required shooting time, and speed-up factor. Copy the plain-text result into a shot plan.
- Confirm that the selected interval is longer than the exposure and write time your camera needs. This calculator does not operate or inspect a camera.
Formula and boundary rule
Forward plan: photos = floor(shooting duration ÷ interval), and video length = photos ÷ fps. Reverse plan: photos = ceil(target video seconds × fps), and shooting duration = photos × interval. The first scheduled photo occurs after one full interval; a capture exactly on the end boundary is included.
Worked examples
One hour, 5-second interval, 30 fps
3,600 ÷ 5 gives 720 photos. At 30 fps, the finished video is 24 seconds long, with a 150× speed-up factor.
A 15-second clip at 24 fps and a 10-second interval
The clip needs 360 photos. Under this boundary rule, the required shooting duration is 3,600 seconds, or 1 hour.
Limits and practical checks
- The count describes scheduled captures, not guaranteed saved files. Missed shots, buffer delays, battery loss and full storage reduce the actual count.
- The interval must leave enough time for exposure, processing and writing. Long exposure and camera-specific restrictions are outside this calculation.
- Playback fps is treated as an ordinary constant. Drop-frame timecode, editing cadence, frame blending and video processing are excluded.
- The tool does not recommend a subject interval, storage capacity, camera, power setup, weather protection or safety procedure.
Frequently asked questions
Why can the result be zero photos?
With this explicit schedule, the first photo happens after one full interval. A shorter shooting window reaches no scheduled capture.
Is a photo at the exact end included?
Yes. For example, 60 seconds with a 10-second interval includes the capture scheduled at 60 seconds and yields 6 photos.
Why round up in target-video mode?
A partial photo cannot be captured. Rounding up supplies at least enough whole frames for the requested clip length.
Does the calculator control my camera?
No. It provides arithmetic only; configure and test your camera or intervalometer separately.