Calories your body burns at rest
Your basal metabolic rate (BMR) is the energy your body uses just to stay alive — breathing, circulation, keeping warm. It makes up most of the calories you burn each day. Enter your sex, age, height and weight to calculate it with the Mifflin–St Jeor equation, considered the most accurate for most people.
Compare with the older Harris–Benedict formula, or use Katch–McArdle if you know your body-fat percentage. A table then shows your maintenance calories for five activity levels.
How to calculate BMR
- 1
Enter your details
Sex, age, height and weight.
- 2
Choose a formula
Mifflin–St Jeor is the default.
- 3
Read your BMR
Calories per day at complete rest.
- 4
Check activity levels
Maintenance calories from sedentary to extra active.
Key features
Three formulas
Mifflin–St Jeor, Harris–Benedict and Katch–McArdle.
Activity table
Daily calories for five activity levels.
Metric and imperial
cm/kg or ft/in and lb.
Instant
Updates as you type.
Common uses
- Diet planning: Know your baseline before setting targets.
- Fitness coaching: Estimate clients' energy needs.
- Learning: Understand how age and muscle affect metabolism.
Tips and good to know
- BMR drops slightly with age and rises with muscle mass — strength training helps keep it up.
- To set a weight-loss or gain target, use the Calorie Calculator.