Know your
body numbers.
BMI, calories, macros, body fat — all in one dashboard. Instant results, no account needed.
Why CalorieBreak?
Most fitness sites bury their calculators behind email signups, app installs, or paywalls. CalorieBreak gives you the same science-backed formulas instantly — completely free, no account needed, no data stored.
Knowing your numbers is the starting point for any body composition goal. Your BMI gives a quick health screening. Your TDEE tells you exactly how many calories you burn each day — the number you need before setting any diet target. Your macro split determines how much of your intake comes from protein, carbohydrates, and fat, which matters most during a cut where protein intake directly affects muscle retention. Your body fat percentage tells you what your BMI cannot: whether your weight is mostly muscle or mostly fat.
These numbers interact. A 1 kg drop on the scale means something different at 30% body fat versus 15%. A calorie deficit that looks aggressive on paper might be perfectly sustainable for someone with a high TDEE. Running all six calculators takes a few minutes and gives you a complete picture of where you are today.
The formulas we use
- BMI: weight(kg) ÷ height(m)² — WHO categories (18.5–24.9 normal)
- BMR/TDEE: Mifflin-St Jeor (1990) × activity multiplier
- Macros: Research-backed percentage splits by goal (cutting/maintenance/bulking)
- Body fat: US Navy circumference method (Hodgdon & Beckett, 1984) — within 1–3% of DEXA
- Ideal weight: Devine, Hamwi, Robinson, and Miller formulas
- Calorie deficit: TDEE-based deficit with Mifflin-St Jeor BMR
Fitness Guides
Not sure what to do with your results? These guides walk through the next steps.