BMR calculator
Basal metabolic rate: the calories your body burns at rest.
About this calculator
This BMR calculator estimates your basal metabolic rate, the energy your body uses at complete rest to breathe, keep warm and keep your organs working.
Compare the main formulas side by side, and see the daily calories you need at different activity levels.
How it works
Mifflin-St Jeor: 10 × weight in kg + 6.25 × height in cm − 5 × age, plus 5 for men or minus 161 for women. Katch-McArdle uses lean mass instead: 370 + 21.6 × lean kg.
Last reviewed:
Worked example
- Units: Feet and pounds
- Sex: Female
- Age: 35 years
- Height: 5 ft 7 in
- Weight: 155 lb
- Formula: Mifflin-St Jeor (recommended)
Your BMR: 1,431 kcal (a day, at complete rest)
Common questions
What is a normal BMR?
It varies with size, age and sex. Many women fall between about 1,200 and 1,500 kcal a day and many men between about 1,500 and 1,900, but larger and more muscular people burn more.
Which BMR formula is most accurate?
Studies suggest Mifflin-St Jeor is the most reliable for most people. Katch-McArdle can be better if you know your body fat percentage accurately.
Can I raise my BMR?
Building muscle raises it a little, since muscle burns more energy than fat at rest. BMR also falls slowly with age and when you lose weight.
Sources and further reading
The story behind it
Where the idea came from: The Mifflin-St Jeor equation was published in 1990 and has since become a standard choice for dietitians.
Researchers led by Mark Mifflin and Sachiko St Jeor measured the resting energy use of nearly 500 adults and found that the older Harris-Benedict equations tended to overestimate it. Their simpler equation fitted modern bodies better. This calculator uses it by default and shows the older formula alongside for comparison.
Why you can trust this calculator
- It runs in your browser. Nothing you type into it is sent anywhere.
- The method is explained on this page, so you can check it yourself.
- Free to use, with no sign-up.
- Results are estimates, not medical advice.
- Spotted a mistake? Tell us and we'll look into it.
After 15 years as a mathematics educator, I built CalculStore to give students, teachers, professionals and anyone working with numbers simple, reliable tools.
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