Estimate basal metabolic rate with Mifflin-St Jeor, revised Harris-Benedict, or Katch-McArdle. Compare BMR formulas and see resting calorie needs.
Use this BMR calculator to estimate your basal metabolic rate, or the calories your body uses at complete rest. It is best for comparing BMR formulas and understanding resting energy needs.
This calculator includes Mifflin-St Jeor, revised Harris-Benedict, and Katch-McArdle. For most adults, Mifflin-St Jeor is the best default. If you know your body-fat percentage, Katch-McArdle can be a stronger estimate because it uses lean body mass. For activity-adjusted maintenance calories, use the TDEE Calculator. For daily calorie intake by goal, use the Calorie Calculator.
Activity level
Formula
Body fat
%
Optional for Katch-McArdle
-
kilocalories per day (kcal/day)
kilojoules per day (kJ/day)
-
kilocalorie per hour (kcal/h)
-
Lean body mass
-
Estimated maintenance calories
- kilocalories per day (kcal/day)
Calorie targets
kilocalories per day (kcal/day) · ±275 / ±550 kcal · TDEE
Daily energy needs by activity
| Sedentary or little exercise | - |
| Light exercise 1-3 days/week | - |
| Moderate exercise 4-5 days/week | - |
| Hard exercise 6-7 days/week | - |
| Very hard exercise / physical job | - |
Formula comparison
| Formula |
BMR (kcal/day) |
Maintenance (kcal/day) |
| Mifflin-St Jeor | - | - |
| Revised Harris-Benedict | - | - |
| Katch-McArdle | - | - |
BMR and calorie targets are estimates. Actual energy needs vary with body composition, hormones, medical conditions, medications, training load, and daily movement. For pregnancy, eating disorders, or clinical nutrition planning, use professional guidance.
BMR Calculator FAQ
What is BMR?
BMR stands for basal metabolic rate. It is the approximate number of calories your body uses in a day at complete rest to support breathing, circulation, temperature regulation, and basic organ function.
What is the difference between BMR and TDEE?
BMR is your baseline energy use at rest. TDEE means total daily energy expenditure, which adds activity, exercise, and daily movement on top of BMR. If you want maintenance calories, TDEE matters more than BMR alone.
Which BMR formula is best?
Mifflin-St Jeor is usually the best starting point for most adults. Revised Harris-Benedict is another common estimate. Katch-McArdle is useful when you know your body-fat percentage because it calculates from lean body mass.
Can I use BMR for weight loss?
Yes, but BMR alone is not your eating target. Most people should use maintenance calories from the activity-adjusted result, then create a moderate calorie deficit for fat loss or a moderate surplus for muscle gain.
Why does the calculator show more than one result?
There is no single perfect formula for every body. A competitive BMR calculator should show the main formulas, maintenance calories by activity level, and practical calorie targets so you can use the estimate in training, dieting, or meal planning.
