BMR & TDEE Calculator

How it works

Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest just to keep you alive — breathing, circulating blood, regulating temperature, repairing cells. Total Daily Energy Expenditure (TDEE) is BMR multiplied by an activity factor that accounts for movement, exercise, and the thermic effect of food. TDEE is your maintenance calorie level — eat that many calories and your weight stays roughly stable.

This calculator uses the Mifflin-St Jeor equation, the modern standard considered most accurate for the general population. The formula is BMR = 10×weight(kg) + 6.25×height(cm) − 5×age(years) ± a sex constant (+5 for male, −161 for female). It improved on the older Harris-Benedict equation by reducing the systematic over-estimate of BMR in modern, less-active populations.

The activity multipliers we use are the standard set: 1.2 (sedentary, desk job, no exercise), 1.375 (light, 1–3 sessions per week), 1.55 (moderate, 3–5 sessions), 1.725 (active, 6–7 sessions), and 1.9 (very active, physical job plus intense daily training). Most people overestimate their activity level — when in doubt, choose one tier lower.

Below your TDEE we display calorie targets for typical weight-management goals. A 500 kcal/day deficit roughly translates to losing 1 lb per week (3,500 kcal ≈ 1 lb of fat); 1,000 kcal/day supports 2 lb/week, but rates above 1% of body weight per week risk significant muscle loss. For weight gain, a 250–500 kcal/day surplus paired with strength training favors lean-mass gains over fat.

These are estimates. Real metabolic rate varies ±10–20% from formula predictions because of individual differences in lean mass, hormones, NEAT (non-exercise activity thermogenesis), and gut microbiome. Track actual changes over 2–4 weeks and adjust.