Free · Instant · Shows the math
BMR Calculator
The calories your body burns at complete rest, from all three equations side by side.
Results
- BMR (Mifflin-St Jeor)
- 1,452 kcal
- Mifflin-St Jeor
- 1,452 kcal
- Harris-Benedict (revised)
- 1,492 kcal
Mifflin-St Jeor Equation
BMR = 10W + 6.25H − 5A − 161
W = weight (kg) · H = height (cm) · A = age (years)
Supply body fat % to add the Katch-McArdle Formula, which works from lean body mass.
Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest to run your heart, lungs, brain, and body temperature. BMR is 60–70% of daily calorie needs for most adults.
This calculator shows all three equations: Mifflin-St Jeor (default), the revised Harris-Benedict Equation, and Katch-McArdle when you supply body fat percentage.
How to calculate BMR
To calculate BMR, put your weight in kilograms, height in centimetres, and age into the Mifflin-St Jeor Equation. The men and women versions differ only by the final constant.
Worked example: a 30-year-old man at 80 kg and 180 cm has BMR = 10×80 + 6.25×180 − 5×30 + 5 = 1,780 kcal.
Frequently asked questions
Most adult BMRs fall between 1,300 and 2,000 calories per day. Larger, younger, and more muscular bodies sit higher; the value drops with age.
Mifflin-St Jeor is the most accurate for the general population. Katch-McArdle is more accurate when you know your body fat percentage.
No. BMR is rest-only. You eat against TDEE — BMR times an activity factor — which is always higher.
Results are estimates based on population averages and are not medical advice. Consult a doctor or registered dietitian nutritionist (RDN) before making large changes to your diet, especially for deficits over 2 lb (0.9 kg) per week, during pregnancy or nursing, or for anyone under 18.