What this calculator does
A macro calculator helps turn a calorie target into practical gram targets for protein, fat and carbohydrate. This version starts with protein per kilogram, sets fat as a share of calories and assigns the remaining calories to carbohydrate.
Formula used
Protein grams equal body weight multiplied by the protein target. Fat grams equal fat calories divided by 9. Carbohydrate grams equal remaining calories divided by 4.
How to read the result
The macro split should support training, health and adherence. It is normal to adjust the targets if food preference, performance or digestion suggests the split is not working.
Assumptions
- Protein and carbohydrate use 4 kcal per gram.
- Fat uses 9 kcal per gram.
- Does not prescribe micronutrients, fibre or meal timing.
Sources and checks
This calculator uses a standard public formula. Where rules or thresholds can change, source links are listed on the relevant page.
Frequently asked questions
What happens if carbs go negative?
That means protein and fat targets use more calories than the daily target allows. Lower one of the targets or raise the calorie budget.