How to use the macro conversion
Enter a daily calorie target that you have already chosen. Then enter the percentage of those calories assigned to carbohydrate, protein, and fat. The three percentages must total 100. Select Convert to grams to see the gram amounts and an energy check.
For a 2,000 kcal target with a 50/20/30 split, carbohydrate is 250 g, protein is 100 g, and fat is about 66.67 g. The tool first assigns calories by percentage, then divides carbohydrate and protein calories by 4 and fat calories by 9.
What this tool does—and does not do
This is a unit conversion for a user-supplied target and split. It does not estimate total daily energy expenditure, choose a calorie deficit, recommend a macro ratio, prescribe meals, or adapt values for a disease, pregnancy, medication, allergy, athletic program, or eating disorder. A larger search category often uses the name “macro calculator,” but this page deliberately performs only the narrower arithmetic stated above.
Zero is allowed for one or two macro shares when the full split still totals 100; acceptance is arithmetic, not a nutritional endorsement. If you need personal intake advice, use a qualified health professional who can consider your circumstances.
Formula, precision, and rounding
The FDA food-label reference lists 9 calories per gram for fat and 4 for carbohydrate and protein. This calculator applies those energy factors: grams = target calories × percentage ÷ 100 ÷ calories per gram. It does not model alcohol, fiber-specific factors, sugar alcohols, or local food-label rounding rules.
Calculations retain full precision and the screen rounds final grams to two decimal places, dropping unnecessary zeros. Because independently rounded gram values may reconstruct a calorie total a few hundredths away from the target, the energy check is calculated from the unrounded amounts. Do not keep rounding intermediate numbers when planning or comparing.
Two more examples
At 1,800 kcal and 45% carbohydrate, 25% protein, and 30% fat, the results are 202.5 g, 112.5 g, and 60 g. At 2,400 kcal and 40/30/30, the results are 240 g carbohydrate, 180 g protein, and 80 g fat.
Editing any value clears the confirmed answer and disables copying. This prevents a result for an older split from remaining visible. Clear removes the values; the muted examples return when empty fields lose focus.
Frequently asked questions
Why must the percentages total 100? The page allocates the entire entered calorie target among exactly these three macronutrients. Does this calculate my ideal calories? No. It only converts the target you provide. Are the grams meal-by-meal? No; they represent the same daily period as your target. Why can my food labels differ? Labels can use rounding and foods contain components beyond this simple allocation. Is a 0% share recommended? No; it is only accepted mathematically.