Macronutrient Split Calculator
Turn a daily calorie target into grams of protein, carbs and fat for balanced, high-protein, low-carb or keto splits.
How it works
Carb g = calories × carb% ÷ 4 · Protein g = calories × protein% ÷ 4 · Fat g = calories × fat% ÷ 9
Macronutrients carry different energy densities — protein and carbohydrate each supply about 4 kcal per gram while fat supplies 9 — so a percentage split only becomes actionable once converted to grams. Higher-protein splits help preserve muscle in a calorie deficit and keep you full, while very low-carb keto splits shift most energy to fat. There is no single best ratio: total calories drive weight change, and the split is tuned for satiety, training and personal preference.
Worked example
At 2,200 kcal on a 40/30/30 split: carbs = 2200 × 0.40 ÷ 4 = 220 g, protein = 2200 × 0.30 ÷ 4 = 165 g, fat = 2200 × 0.30 ÷ 9 = 73 g.
Frequently asked questions
Why divide protein and carbs by 4 but fat by 9?
Those are the Atwater energy values: protein and carbohydrate release about 4 kcal per gram, and fat about 9 kcal per gram. Dividing each macro’s calorie share by its value gives grams.
What macro split is best for fat loss?
Total calories matter most, but a higher-protein split (30–40% of calories) helps retain muscle and control hunger while dieting. Beyond that, choose carb and fat levels you can stick to.
How much protein is too much?
For most people, protein up to around 2 g per kg of body weight is safe and useful. Very high intakes are not harmful for healthy kidneys but rarely add benefit past that point.
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Educational estimate using standard formulas and population averages — not medical advice. Talk to a qualified clinician before making decisions about diet, training, or pregnancy.