BMR Calculator

BMR (basal metabolic rate) is the number of calories your body burns at complete rest to keep you alive — breathing, circulation, cell production and temperature regulation. It does not include activity, digestion or exercise.

For men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5. For women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161. The result is in kcal/day. It is the equation most dietitians use today.

It is the most accurate of the widely used predictive equations, typically within about ±10% of measured values for most adults. Individual metabolism varies, so treat the result as a starting estimate, not a medical measurement.

The Harris-Benedict equation (originally 1919, revised 1984) was derived from an older population sample and tends to overestimate BMR by roughly 5% compared with Mifflin-St Jeor. This tool uses the revised 1984 Harris-Benedict formula as a comparison option.

TDEE (total daily energy expenditure) estimates all calories you burn in a day: BMR × an activity multiplier. This tool uses 1.2 (sedentary), 1.375 (light), 1.55 (moderate), 1.725 (very active) and 1.9 (extra active).

A common guideline is a 500 kcal/day deficit below your TDEE, which theoretically leads to about 0.5 kg of weight loss per week. Never go below about 1200 kcal/day (women) or 1500 kcal/day (men) without medical supervision.

Yes, on average. The equations reflect this: at the same weight, height and age, the Mifflin-St Jeor formula gives women a BMR about 166 kcal lower than men, largely because of differences in average muscle mass.

Yes. Switch the unit toggle to Imperial; the calculator converts pounds to kilograms (1 lb = 0.45359237 kg) and feet/inches to centimeters (1 in = 2.54 cm) before applying the formulas, so results are identical.

Yes. Both equations subtract about 5 kcal per year of age, reflecting roughly a 1–2% decline per decade after early adulthood, mostly from gradual muscle loss.

No. This tool is for educational purposes only. It does not diagnose or treat any condition. If you have a medical condition, are pregnant, or are planning a major diet change, talk to a doctor or registered dietitian.

This tool focuses on the Mifflin-St Jeor equation as the default and adds practical TDEE and calorie-goal planning. The separate Harris-Benedict tool covers the original 1919 versus revised 1984 equations and their history in depth.

Different calculators use different equations (Mifflin-St Jeor, Harris-Benedict original or revised, Katch-McArdle), round differently, or apply different activity multipliers. Differences of 50–150 kcal are normal between equations.