BMR Calculator

Your basal metabolic rate (BMR) is what your body burns at complete rest. See it with three well-known equations side by side, so you know how much the estimate can vary.

Your details

years
kg
Sex
cm
%

Your results

Enter your age, height and weight to see your BMR.

How to use it

  1. Choose your units, then enter your sex, age, height and weight.
  2. If you know your body fat %, add it to also get the lean-mass (Katch-McArdle) estimate.
  3. Read your BMR. The main number uses Mifflin-St Jeor; the table compares all three.
  4. For your total daily burn, including activity, use the TDEE Calculator.

How it's calculated

The calculator uses three published equations. W is weight in kg, H height in cm, A age in years, LBM lean body mass in kg.

Mifflin-St Jeor (1990), the main result:

  • Men: 10 × W + 6.25 × H − 5 × A + 5
  • Women: 10 × W + 6.25 × H − 5 × A − 161

Harris-Benedict, revised by Roza and Shizgal (1984):

  • Men: 88.362 + 13.397 × W + 4.799 × H − 5.677 × A
  • Women: 447.593 + 9.247 × W + 3.098 × H − 4.330 × A

Katch-McArdle (the lean-mass equation from Cunningham, 1991): 370 + 21.6 × LBM, where LBM = W × (1 − body fat % ÷ 100). The same equation for men and women.

All results are in kcal a day and rounded to the nearest 10 kcal; the equations aren’t more precise than that. Pounds, feet and inches are converted to kg and cm first.

Limits. These equations predict the average for people like you. Your real BMR can be 10% or more above or below it. Only a lab measurement (indirect calorimetry) tells you exactly.

Sources

  1. 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. American Journal of Clinical Nutrition, 51(2), 241–247.
  2. Roza, A. M., & Shizgal, H. M. (1984). The Harris Benedict equation reevaluated: resting energy requirements and the body cell mass. American Journal of Clinical Nutrition, 40(1), 168–182.
  3. Cunningham, J. J. (1991). Body composition as a determinant of energy expenditure: a synthetic review and a proposed general prediction equation. American Journal of Clinical Nutrition, 54(6), 963–969.
  4. 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.

Questions

Which BMR equation is most accurate?

For most adults, Mifflin-St Jeor. A systematic review (Frankenfield and colleagues, 2005) found it predicted resting energy within 10% for more people than the other equations it tested. That's why it's the main number here.

When should I use Katch-McArdle?

When you know your body fat % reasonably well and you're more muscular or leaner than average. It uses lean mass only, so it doesn't need your sex or age. A rough body fat guess makes it less accurate, not more.

What's the difference between BMR and TDEE?

BMR is what you burn lying still all day. TDEE adds everything you do on top, like walking, work, training and digesting food. TDEE is the number to plan your eating around; the TDEE Calculator works it out.

Why do the equations give different numbers?

Each was built from a different group of people, measured in a different decade. Differences of 5 to 10% are normal. Treat your BMR as a range, not an exact figure.

Updated November 9, 2026.