Macro Calculator

A macro calculator turns a daily calorie target into grams of protein, carbohydrate and fat, which is what food labels and tracking apps count. Estimate your calories from your body details and goal, or type in a target you already have, then choose a balanced, higher-protein, lower-carb, keto or custom split.

How to use this tool

1. Enter body details, activity and goal to estimate calories, or supply a target and weight for the grams-per-kilogram comparison.
2. Choose a macro split, or pick Custom and enter percentages that add up to 100.
3. Read your daily grams; the first table also divides them across three meals.
4. Compare the other splits at the same calories in the second table.

Formula

Protein grams = calories × protein share ÷ 4; carbohydrate grams = calories × carb share ÷ 4; fat grams = calories × fat share ÷ 9 (shares as fractions, e.g. 20% = 0.20)

Protein and carbohydrate supply about 4 kcal per gram and fat about 9 kcal per gram (the Atwater factors). Without a target, calories come from the Mifflin-St Jeor BMR × activity factor plus the goal adjustment. US Dietary Reference Intakes suggest adults get 45–65% of calories from carbohydrate, 10–35% from protein and 20–35% from fat. The stated distribution ranges apply from age 19. Presets are examples of allocation, not recommendations for every user.

Example

At 2,000 kcal with the balanced split (50% carbs, 20% protein, 30% fat): carbs = 2,000 × 0.50 ÷ 4 = 250 g, protein = 2,000 × 0.20 ÷ 4 = 100 g and fat = 2,000 × 0.30 ÷ 9 = 67 g a day. Over three meals that is about 83 g of carbs, 33 g of protein and 22 g of fat each.