Macro Calculator

It first works out your daily calorie target from TDEE and your goal, then applies your chosen ratio's percentages to that number. Protein and carbs are converted at 4 kcal per gram, fat at 9 kcal per gram — the Atwater factors that have been the basis of nutrition labeling since the 1890s. So a 30% protein share of 1,701 kcal becomes 1,701 x 0.30 / 4 = 128 g.

Balanced is 40% carbs / 30% protein / 30% fat, High Protein shifts to 30/40/30, and Low Carb is 25% carbs / 40% protein / 35% fat. The Low Carb preset here is a moderate reduction, not a ketogenic split — true keto diets typically run below 10% carbohydrate, well past what this preset offers.

Because a percentage moves with your total calories in a way that doesn't reflect your body weight — 40% protein at 1,200 kcal is only 120 g, while the same 40% at 3,000 kcal is 300 g, and neither was actually chosen for your size. The stronger evidence in sports nutrition is for protein as grams per kilogram of body weight (the ISSN position stand cites 1.6-2.2 g/kg), so it's worth cross-checking the gram total against that range directly, especially at an unusually low or high calorie target.

From the same Mifflin-St Jeor TDEE calculation used across this site's calorie tools: BMR from your age, sex, height, and weight, times an activity factor, then a flat adjustment for your goal — weight loss subtracts 500 kcal, muscle gain adds 300 kcal, both floored at a sex-specific safety minimum before the macro split is applied.

Not on its own. Diagnosed conditions with specific macronutrient guidance should override a percentage-based split entirely, and endurance athletes with high training volume have carbohydrate needs tied to that training load, which a fixed percentage doesn't capture. This calculator is built for general fitness goals in healthy adults, not clinical or high-performance nutrition planning.