BMR Calculator
Your basal metabolic rate — the calories your body burns doing absolutely nothing — by the two standard formulas.
BMR vs TDEE
BMR is the floor: heart, brain, breathing, cell repair. Your total daily burn (TDEE) adds movement on top — from ~1.2× BMR for a desk-bound day to ~1.9× for hard physical work. For calorie targets that include activity, use our calorie calculator.
Frequently asked questions
Why two formulas, and which is better?
Harris-Benedict (1919, revised 1984) came first; Mifflin-St Jeor (1990) was fitted on modern populations and is the one dietitians default to today. They usually land within ~50 kcal of each other — treat the pair as a range, not a verdict.
Why is eating below BMR a bad idea?
Sustained intake below BMR is a crash diet: muscle loss, hormone disruption and rebound. Fat-loss targets normally sit between BMR and TDEE — a moderate deficit off your total burn, not your resting floor.
Can I raise my BMR?
Meaningfully, only by adding muscle — each kilogram of muscle burns roughly 13 kcal/day at rest versus 4.5 for fat. Caffeine and cold showers make headlines but move the number by rounding-error amounts.
Last updated: 2026-07-13