Macro Calculator
Split a daily calorie target into protein, carbohydrate, and fat grams based on a chosen macro percentage split.
- Free to use
- Accurate results
- No registration required
- Works on all devices
Your result
150 g/day
Protein
AI explanation
Formula
Grams = calories × percent / 100 / kcal-per-gram (protein & carbs: 4 kcal/g, fat: 9 kcal/g)Worked example
2000 kcal at a 30/40/30 split
| Field | Value |
|---|---|
| Daily calorie target | 2000 |
| Protein | 30 |
| Carbohydrates | 40 |
| Fat | 30 |
| Protein | 150 |
| Carbohydrates | 200 |
| Fat | 67 |
Assumptions
- Uses the Atwater energy factors (4 kcal/g for protein and carbohydrate, 9 kcal/g for fat).
- Your three percentages must add up to 100%.
- Informational only — not personalized medical or dietary advice.
Frequently asked questions
What macro split should I use?
A common starting point is 30% protein / 40% carbs / 30% fat, but the right split depends on your goals (fat loss, muscle gain, endurance) and personal preference — there's no single universally optimal ratio.
Why do protein and carbs use 4 kcal/g but fat uses 9?
These are the Atwater energy factors, reflecting how many calories each macronutrient actually yields per gram when metabolized. Fat is more energy-dense than protein or carbs.
What if my percentages don't add up to 100%?
The calculator requires protein, carb, and fat percentages to sum to 100% — adjust one of the three so they do.
Related calculators
Sources
- Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids — National Academies (Institute of Medicine). Effective 01-01-2005, reviewed 13-09-2026.
This calculator provides a general estimate only and does not constitute personalized medical, nutritional, or fitness advice. Consult a registered dietitian for a personalized nutrition plan.
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