BMR & Calorie Calculator
Calculate your Basal Metabolic Rate and daily calorie needs based on your activity level.
Total Daily Energy Expenditure (TDEE)
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kcal/day
Mifflin-St Jeor
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kcal/day
Harris-Benedict
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kcal/day
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What is Basal Metabolic Rate (BMR)?
Basal Metabolic Rate (BMR) is the number of calories your body needs to maintain basic physiological functions at complete rest — breathing, circulation, cell production and temperature regulation. It represents 60–75% of total daily energy expenditure and is the foundation for calculating nutritional needs.
How is it calculated?
Basal Metabolic Rate (BMR) is the energy the body expends at complete rest to maintain vital functions. There are three main formulas used to estimate it: the Mifflin–St Jeor equation (1990), considered the most accurate for the general population according to the Academy of Nutrition and Dietetics; the Harris–Benedict equation revised by Roza and Shizgal (1984), an update of the original 1919 formula; and the Katch–McArdle formula, the most accurate for individuals who know their fat‑free mass because it removes body fat from the calculation.
Formula
Mifflin - Men: BMR = (10 × kg) + (6.25 × cm) − (5 × age) + 5Mifflin - Women: BMR = (10 × kg) + (6.25 × cm) − (5 × age) − 161Revised Harris–Benedict — Men: 88.362 + (13.397 × kg) + (4.799 × cm) − (5.677 × age)Katch–McArdle: BMR = 370 + (21.6 × fat‑free mass in kg)⚠️ Limitations
All BMR formulas are estimates with a ±10% margin of error compared to laboratory‑measured metabolic expenditure. Stress, sleep, body temperature, and hormonal status affect true BMR but are not accounted for in any equation.