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Macro Calculator
Daily calories split into protein, carbohydrate and fat grams.
Protein per day
How it works
Protein grams = calories × protein% ÷ 4 Carbohydrate grams = calories × carb% ÷ 4 Fat grams = calories × fat% ÷ 9 Protein and carbohydrate carry 4 kcal per gram; fat carries 9 kcal per gram.
Worked example: 2,000 kcal at 30% protein, 40% carbohydrates and 30% fat gives protein 2,000 × 0.30 ÷ 4 = 150 g, carbohydrates 2,000 × 0.40 ÷ 4 = 200 g, and fat 2,000 × 0.30 ÷ 9 = 66.67 g. The three percentages add to 100%, so the grams account for all 2,000 kcal.
Frequently asked questions
Why is fat divided by 9 and the others by 4?
Because a gram of fat carries about 9 kcal, while a gram of protein or carbohydrate carries about 4 kcal. The divisor is the energy per gram, not a preference for one macro over another.
What if my percentages do not add to 100%?
Then the grams account for only that share of the calories. The calculator shows the total percentage, so a total of 90% means 10% of the calories are unassigned — adjust one percentage to close the gap.
Is this medical or diet advice?
No. This is an informational calculation only. For a personal nutrition plan, especially with a health condition, speak to a qualified professional rather than relying on a percentage split.
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