Estimate your Basal Metabolic Rate using the revised Harris-Benedict equation.
Men: BMR = 13.397w + 4.799h - 5.677a + 88.362
Women: BMR = 9.247w + 3.098h - 4.330a + 447.593
For general wellness information only — not medical advice. Consult a healthcare professional for personal guidance.
BMR (basal metabolic rate) is the energy your body burns just staying alive — breathing, circulating blood, maintaining organ function — with zero activity added, and it's usually the largest single component of your total daily calorie burn. There are two well-known formulas for estimating it, and they don't agree: the original Harris-Benedict equation dates to 1919 and tends to overestimate BMR by 5–15% for modern, less physically laborious lifestyles, while the newer Mifflin-St Jeor equation (1990) has been validated against measured metabolic data more accurately, particularly for people who are overweight or obese, and is the formula recommended by the American Dietetic Association and Dietitians of Canada.
Mifflin-St Jeor calculates BMR from weight, height, age and sex: for men it's 10×weight(kg) + 6.25×height(cm) − 5×age + 5, and for women it's the same minus 161 instead of plus 5. No formula based only on these four inputs can be exact — actual metabolic rate is also shaped by muscle mass, genetics, thyroid function and other factors that a height/weight/age formula can't see — so treat the result as a solid starting estimate (typically within about 10% of a lab measurement for most people) rather than a lab-grade number.
Mifflin-St Jeor (1990) has been shown in multiple studies to track measured resting metabolic rate more closely than the older 1919 Harris-Benedict formula, especially for overweight and obese individuals, and it's the equation recommended by the American Dietetic Association. Harris-Benedict tends to overestimate BMR by 5–15% for typical modern activity levels.
Formula-based BMR estimates from height, weight, age and sex are typically within about 10% of a measured value (from indirect calorimetry) for most people, which is close enough for practical calorie planning. Individual variation in muscle mass, genetics and metabolic health means it can't match a direct lab measurement exactly.
No — BMR is only the energy needed at complete rest. Your total daily energy expenditure (TDEE) adds digestion, daily movement and exercise on top of BMR, and for most people TDEE ends up 20–90% higher than BMR depending on activity level, which is why a separate TDEE/calorie calculator exists for planning actual intake.
Men typically carry a higher proportion of muscle mass than women at the same height and weight, and muscle tissue burns more energy at rest than fat tissue does. That's reflected directly in the Mifflin-St Jeor formula, which adds 5 for men and subtracts 161 for women — a built-in adjustment for this typical difference in body composition, not a statement about any individual.