Your Basal Metabolic Rate is the energy your body burns doing nothing at all — keeping your heart beating, your lungs working and your temperature steady. It is the floor your daily calorie needs are built on. Enter your details below to estimate it.
Estimates using the Mifflin-St Jeor and Katch-McArdle equations. A starting point — adjust from 2–3 weeks of real-world results.
Which equation should you trust?
This calculator runs two, and they answer the same question differently:
- Mifflin-St Jeor uses your height, weight, age and sex. It is the current standard for the general population and needs nothing you do not already know.
- Katch-McArdle works from your lean body mass instead of total weight, so it needs a body-fat percentage. If you carry more muscle than average, this is the more accurate of the two — because muscle is metabolically active in a way that fat is not.
In practice: if you do not know your body fat, use Mifflin-St Jeor and move on. If you do know it and you are lean or muscular, trust Katch-McArdle — the gap between the two widens the further you sit from average body composition.
BMR is not the number you eat
This trips people up constantly. BMR is what you would burn lying in bed all day. It does not include walking to the kitchen, your job, your commute or your training. Eating at your BMR is almost always a steep, unsustainable deficit.
The number you actually plan meals around is your TDEE — your BMR multiplied by an activity factor. Run the TDEE calculator for that, then split it into protein, carbs and fat with the macro calculator.
Frequently asked questions
What is a normal BMR?
It varies enormously with size, sex, age and muscle mass. A rough guide is 1,400–1,800 kcal/day for many adult women and 1,600–2,100 for many adult men — but your own figure above is more useful than any average.
Can I raise my BMR?
Somewhat, and slowly. Adding muscle raises it because lean tissue burns more at rest than fat does — but the effect is modest, not transformative. Crash dieting pushes it the other way.
Why do BMR calculators disagree?
Because they use different equations fitted to different populations. Any estimate carries a margin of error of roughly 10%, which is why you should treat the output as a starting point and adjust from 2–3 weeks of real results.
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