Recipe Macros Per Serving Calculator
Enter a recipe’s total protein, carbs and fat, split by servings, and see per-portion macros plus the calories those grams add up to.
How it works
Per serving = total grams ÷ servings · kcal = protein·4 + carbs·4 + fat·9 (per gram)
The Atwater factors treat protein and carbohydrate as roughly 4 kcal per gram and fat as 9 kcal per gram, so a recipe’s calories fall out of its macros directly. Total each macro across all ingredients, divide by servings, and multiply out to check the calorie count. This simple model ignores fibre and alcohol, so it slightly overstates calories for very high-fibre dishes.
Worked example
A recipe totals 120 g protein, 200 g carbs and 60 g fat: that is 480 + 800 + 540 = 1,820 kcal. Over 4 servings, each portion has 30 g protein, 50 g carbs, 15 g fat and about 455 kcal.
Frequently asked questions
Why do the grams times 4/4/9 not exactly match a label?
The 4/4/9 Atwater factors are averages. Labels may use more precise factors, subtract fibre from carbohydrate, or round each line separately, so a few percent difference is normal and nothing to worry about for home cooking.
Should I count fibre in the carbs?
This calculator uses total carbohydrate at 4 kcal per gram. If you prefer net carbs, subtract fibre grams before entering the carb total, which slightly lowers the calorie estimate since fibre yields little usable energy.
Where do I get the total macro grams?
Add each ingredient’s protein, carbs and fat from its label or a nutrition database, scaled to the amount used, then enter the three totals here. The calculator handles the per-serving split and the calorie math.
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This calculator is for educational purposes. Double-check important results before acting on them.