BMR Calculator

Estimate your Basal Metabolic Rate — the calories your body burns at complete rest — with three standard formulas.

Sex

Adds the Katch-McArdle formula.

What is BMR?

Basal Metabolic Rate (BMR) is the number of calories your body burns in a day at complete rest, just to keep you alive: breathing, circulating blood, keeping your temperature steady, and running your organs. For most people it's the largest part of daily energy use, around 60–70% of it. Everything else — moving around, exercise, and digesting food — is added on top to give your total daily energy expenditure (TDEE).

How BMR is calculated

Measuring BMR directly takes a lab, so calculators use equations fitted to people who were measured. This one gives three. The Mifflin-St Jeor equation (1990) is the most accurate for most adults and is the one we recommend:

Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5

Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161

The Harris-Benedict equation dates from 1918; this calculator uses the 1984 revision by Roza and Shizgal, which tends to come out slightly higher than Mifflin-St Jeor. If you enter your body fat percentage, it also shows the Katch-McArdle formula, which works from lean body mass instead of sex and age:

Katch-McArdle: BMR = 370 + 21.6 × lean body mass (kg)

How to use this calculator

Choose Metric or US units, enter your sex, age, height, and weight, and add your body fat percentage if you know it. Press Calculate BMR to see each formula's estimate and a table of how many calories you burn a day at each activity level. Don't know your body fat? The Body Fat Calculator estimates it from a few tape measurements.

BMR vs. TDEE

BMR is what you'd burn lying still all day; TDEE is what you actually burn, including activity. You can't live at your BMR, so don't use it as a calorie target — eating below it for long periods makes it hard to get enough nutrients. Base your target on TDEE instead: the TDEE & Maintenance Calorie Calculator turns it into targets for losing or gaining weight, and the Calories Burned Calculator shows what a single workout adds.

Limitations

Every BMR formula is a population average. Two people with the same stats can differ by a few hundred calories a day because of muscle mass, genetics, and hormones, and the formulas are less accurate for very muscular people and for people with obesity. Treat the result as a starting estimate and adjust it from your real-world progress. See the Disclaimer for details.

Read the science

References

The formulas and figures on this page come from these sources. Our Editorial Policy explains how they're chosen and checked.

  • Mifflin-St Jeor equation: Mifflin, M. D., St Jeor, S. T., Hill, L. A., Scott, B. J., Daugherty, S. A., & Koh, Y. O. (1990). A new predictive equation for resting energy expenditure in healthy individuals. The American Journal of Clinical Nutrition, 51(2), 241–247. doi:10.1093/ajcn/51.2.241
  • Mifflin-St Jeor as the most accurate equation: Frankenfield, D., Roth-Yousey, L., & Compher, C. (2005). Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: A systematic review. Journal of the American Dietetic Association, 105(5), 775–789. doi:10.1016/j.jada.2005.02.005
  • Original Harris-Benedict equation: Harris, J. A., & Benedict, F. G. (1918). A biometric study of human basal metabolism. Proceedings of the National Academy of Sciences, 4(12), 370–373. doi:10.1073/pnas.4.12.370
  • Revised Harris-Benedict equation: Roza, A. M., & Shizgal, H. M. (1984). The Harris Benedict equation reevaluated: Resting energy requirements and the body cell mass. The American Journal of Clinical Nutrition, 40(1), 168–182. doi:10.1093/ajcn/40.1.168
  • Lean-mass equation (370 + 21.6 × lean mass, known as Katch-McArdle): Cunningham, J. J. (1991). Body composition as a determinant of energy expenditure: A synthetic review and a proposed general prediction equation. The American Journal of Clinical Nutrition, 54(6), 963–969. doi:10.1093/ajcn/54.6.963