Macro Calculator

What Are Macros?

Macronutrients are the three nutrients your body needs in large amounts: protein (4 cal/g), carbohydrates (4 cal/g), and fat (9 cal/g). Each plays a distinct role in your body, and the right balance depends on your goals.

How This Calculator Works

This macro calculator estimates your Total Daily Energy Expenditure (TDEE) — how many calories you burn per day — then divides those calories into protein, carbs, and fat based on your goal.

The calculator supports two BMR formulas:

• Mifflin-St Jeor (default): Uses height, weight, age, and gender. Accurate for most people with average body composition.
• Katch-McArdle (when you enter body fat %): Uses lean body mass, making it more accurate for muscular or obese individuals. BMR = 370 + (21.6 × lean mass in kg).

If you know your body fat percentage, enter it above to switch to the Katch-McArdle formula. Don't know your body fat? Use our body fat calculator to estimate it.

Macro Splits by Goal

Why Protein Matters Most

Protein is the most important macro for body composition. It preserves muscle during weight loss, builds muscle during a surplus, and has the highest thermic effect — 20-30% of protein calories are burned during digestion alone. That means eating 100 calories of protein nets you only 70-80 usable calories, making it harder to overeat. Prioritize hitting your protein target above all else.

Why Body Fat Percentage Matters

Two people who weigh 200 lbs can have very different caloric needs. Someone at 15% body fat has significantly more lean mass (and a higher metabolism) than someone at 35% body fat. By entering your body fat percentage, this calculator uses lean body mass to give you a more precise BMR — and therefore more accurate macro targets.

Adjusting Over Time

• Track weight weekly (same conditions) for 2-3 weeks before adjusting.
• Not losing weight? Reduce calories by 10% (mostly from carbs or fat).
• Not gaining? Add 200 calories (mostly from carbs).
• Feeling fatigued? You may need more carbs, especially around workouts.
• Losing strength? Increase protein to 1g per pound of body weight.

Related Data

Look up nutrition facts, macros, and ingredients for 2M+ foods at GetFoodFacts. Check supplement and vitamin data at PlainVitamins.

Disclaimer: This calculator provides estimates for informational purposes only. Individual needs vary based on genetics, medical conditions, and other factors. Consult a registered dietitian for personalized nutrition advice.