Macronutrient Calculator
Split a daily calorie target into grams of protein, carbs and fat — enter your calories and the percentage for each macro.
Reviewed by the OmniCalc teamMethod verified 2026-07-01
150g protein
Protein 150 grams, carbs 200 grams, fat 66.67 grams- Carbs
- 200 g
- Fat
- 66.67 g
- Protein
- 150
Show steps
- Protein: 2,000 × 30% ÷ 4 = 600 kcal ÷ 4 = 150 g.
- Carbs: 2,000 × 40% ÷ 4 = 800 kcal ÷ 4 = 200 g.
- Fat: 2,000 × 30% ÷ 9 = 600 kcal ÷ 9 = 66.666667 g.
General guideline only — not medical or dietetic advice. Macro needs vary with your goals, activity and individual factors.
How to use the macronutrient calculator
- 1Enter your daily calories (for example from the TDEE calculator).
- 2Set the protein, carbs and fat percentages — they should total 100%.
- 3Read the grams of each macro, with the maths under Show steps.
4 · 4 · 9 — the macro calories
Protein and carbs each supply 4 kcal per gram, while fat supplies 9 kcal. That is why the same percentage of calories turns into fewer grams of fat than of protein or carbs. Treat the result as a starting point, not a prescription — talk to a dietitian for a plan tailored to you.
Frequently asked questions
How are the macro grams calculated?
Each macro gets its share of the calories, then converts to grams using its energy value: protein and carbs are 4 kcal per gram and fat is 9 kcal per gram. So proteinG = calories × protein% ÷ 4, carbsG = calories × carbs% ÷ 4, and fatG = calories × fat% ÷ 9.
Why is fat divided by 9 and not 4?
Fat is more energy-dense: it supplies about 9 calories per gram, while protein and carbohydrate each supply about 4. That is why the same percentage of calories yields fewer grams of fat than of carbs.
What if my percentages don't add up to 100?
The calculator still works — it converts each share to grams exactly as you enter it — but it flags that the split is off balance. For a standard plan the three percentages should total 100%.
What's a good starting split?
A common balanced starting point is 30% protein, 40% carbs and 30% fat, which is why those are the defaults. Athletes, low-carb and other goals shift the ratio, so adjust to fit your plan.