Your basal metabolic rate (BMR) is the number of calories your body burns in 24 hours if you did nothing but rest — it funds your heartbeat, breathing, brain and cell repair.
This calculator uses the Mifflin-St Jeor equation, the most accurate widely used BMR formula, entered with your sex, age, weight and height.
For educational purposes only — not medical advice.
How to use
- Select your sex.
- Enter your age in years.
- Enter your weight in kilograms and height in centimeters.
- Press Compute to see your BMR.
- Use the result as the floor for any calorie planning — never eat below it for long stretches without professional advice.
Frequently asked questions
What is BMR?
Basal metabolic rate is the energy your body expends at complete rest to run its essential functions. It is usually the largest share of the calories you burn each day.
Which formula does this calculator use?
The Mifflin-St Jeor equation: 10 × kg + 6.25 × cm − 5 × age, plus 5 for men or minus 161 for women. Studies have found it estimates measured resting metabolism more accurately than the older Harris-Benedict equation.
Why does BMR fall with age?
Muscle is metabolically active tissue, and the average adult loses some of it every decade after their twenties. Keeping strength training in your routine slows that decline.
Is BMR the same as the calories I burn daily?
No. Daily burn is BMR plus all activity and digestion — typically 1.2 to 1.9 times your BMR depending on how active you are. That daily figure is what TDEE calculators estimate.
Should I eat fewer calories than my BMR?
Sustained eating far below BMR makes nutrition and energy levels hard to manage and is best attempted only under professional supervision.
Does pregnancy change BMR?
Yes — pregnancy raises energy needs substantially, so a pre-pregnancy BMR is not an appropriate target during pregnancy. Follow medical guidance instead.