Basal Metabolic Rate (BMR) Calculator

About this calculator

This calculator estimates BMR — the calories your body burns at complete rest just to keep basic functions running (breathing, circulation, cell repair) — using the modern Mifflin-St Jeor equation: for men, BMR = 10×weight(kg) + 6.25×height(cm) − 5×age + 5; for women, subtract 161 instead of adding 5. It's widely regarded as more accurate for most people than the older Harris-Benedict formula.

Dietitians and fitness trainers multiply BMR by an activity factor (1.2 for sedentary up to ~1.9 for very active) to get TDEE (total daily energy expenditure), the number used to set calorie targets for weight loss, maintenance, or muscle gain. Anyone planning a diet or training program uses this as the starting baseline before adjusting for goals.