Macro Calculator

Calories Set the Budget, Macros Decide How You Spend It

Hitting a daily calorie number is only half of a nutrition plan — the split between protein, carbohydrate, and fat determines whether that budget supports muscle, satiety, and energy the way you want it to. This calculator takes your calorie target and applies one of three common macro splits, so the grams add up correctly to the calories you're actually eating.

The Formula

BMR (Mifflin-St Jeor) × Activity Multiplier + Goal Adjustment = Daily Calories

Protein (g) = (Calories × Protein %) ÷ 4
Carbohydrates (g) = (Calories × Carb %) ÷ 4
Fat (g) = (Calories × Fat %) ÷ 9

Protein and carbohydrate each supply roughly 4 kcal per gram; fat supplies about 9 kcal per gram — the standard Atwater energy conversion values used throughout nutrition science.

The Three Diet Splits

Macro splits available in this calculator
Diet type	Protein	Carbs	Fat
Balanced	30%	40%	30%
Low-Carb	40%	20%	40%
High-Protein	40%	30%	30%

Matching the Split to the Goal

Muscle building — higher protein splits support recovery and lean tissue growth during resistance training.
Fat loss while preserving muscle — higher protein percentages help maintain satiety and lean mass during a calorie deficit.
Endurance training — the balanced or higher-carb split fuels glycogen stores for longer training sessions.
Low-carb approaches — some people find appetite control easier with fat and protein taking a larger share of calories.

How to Use This Calculator

Choose Metric or Imperial units.
Select Male or Female.
Enter your age, weight, and height.
Choose your activity level.
Choose your goal — Weight Loss, Maintain Weight, or Weight Gain.
Choose a diet type — Balanced, Low-Carb, or High-Protein.
Select Calculate to see your daily protein, carb, and fat targets in grams.

Related Calculations

Build each macro individually with the Protein Calculator and Carbs Calculator, or check the calorie total behind it with the TDEE Calculator.