BMR Calculator
Enter your age, height and weight and we estimate how many calories your body burns each day just to keep you alive.
This calculator gives general estimates for information only. It is not medical advice and does not replace a consultation with a doctor or other qualified health professional.
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The formula
Mifflin-St Jeor: men = 10 x kg + 6.25 x cm - 5 x age + 5. Women = 10 x kg + 6.25 x cm - 5 x age - 161.
What BMR is
Your basal metabolic rate is the energy used for breathing, circulation, temperature control and keeping organs working while you are completely at rest. For most adults it makes up about 60 to 70 percent of the calories they burn in a day.
The formulas we use
- Mifflin-St Jeor (1990): the main result. The most accurate for most people.
- Revised Harris-Benedict (1984): the classic equation, which tends to run a little higher.
- Katch-McArdle: shown if you enter your body fat percentage, and best for lean or very muscular people.
A worked example
A 30 year old man, 180 cm and 80 kg: 10 x 80 + 6.25 x 180 - 5 x 30 + 5 = 800 + 1125 - 150 + 5 = 1,780 calories a day at rest. With light exercise a few days a week (x1.375) he would need about 2,450 to maintain his weight.
Do not eat below your BMR for long
Eating well under your BMR for weeks can cost you muscle, energy and mood. If you are trying to lose weight, a moderate deficit from your maintenance level is safer than aiming for your BMR. Speak to a doctor or dietitian before following very low calorie plans.
Examples to check
Type these into the calculator above to see how it behaves. Every result below was produced by the same calculator code that runs on this page.
| What you enter | What you get |
|---|---|
| Male; Age (years): 30; Height (cm): 180; Weight (kg): 80 | BMR (Mifflin-St Jeor): 1,780 kcal/day |
| Female; Age (years): 30; Height (cm): 165; Weight (kg): 65 | BMR (Mifflin-St Jeor): 1,370 kcal/day |
| Female; Age (years): 45; Height (cm): 160; Weight (kg): 70 | BMR (Mifflin-St Jeor): 1,314 kcal/day |
| Male; Age (years): 55; Height (cm): 175; Weight (kg): 90 | BMR (Mifflin-St Jeor): 1,724 kcal/day |
BMR Calculator: frequently asked questions
What is the difference between BMR and TDEE?
BMR is what you would burn lying in bed all day. TDEE (total daily energy expenditure) adds movement and exercise on top. Use BMR as the floor and TDEE for planning how much to eat.
Which BMR formula is most accurate?
The Mifflin-St Jeor equation is the one most dietitians use, and studies find it closest on average. Katch-McArdle is better if you know your body fat percentage, because it uses lean mass.
Can I rely on this result as medical advice?
No. It is a general estimate for information only. It cannot replace a check-up, and your doctor can interpret the numbers for your own situation.
Is what I enter in this calculator saved or sent anywhere?
No. The calculation runs in your browser, so what you enter is not sent to our servers. We only count, anonymously, whether a tool ran successfully.
Is this calculator free to use?
Yes. It is free, needs no sign-up and has no usage limit.
Last reviewed: October 3, 2026