Macro Calculator
Protein, carbs, and fat targets from calories.
Inputs
This calculator gives a general estimate and isn't medical advice. It doesn't account for your individual health history — talk to a doctor before making decisions based on it.
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Formula
Protein (g) = calories × protein% ÷ 4; Fat (g) = calories × fat% ÷ 9; Carbs fill the remainder at 4 kcal/g
You set total daily calories and protein/fat percentages; carbs take whatever is left after protein and fat claim their share of the calorie budget.
Worked example
On 2,000 kcal with 30% protein and 25% fat, the split is about 150 g protein, 225 g carbs, and 56 g fat — the remaining 45% of calories goes to carbohydrates.
Where this can give the wrong answer
- If protein% plus fat% exceeds 100%, the calculator errors out — there's no room left for carbs.
- Grams are rounded to whole numbers, so the three macros may sum to a few calories shy of your exact calorie target.
- Very high protein percentages (above ~40%) on low calories can leave impractically small fat allotments for hormone health.
FAQ
- Those are standard Atwater general factors: protein and carbohydrate yield about 4 kilocalories per gram digested; fat yields about 9. Alcohol (not used here) would be 7 kcal/g.