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BMR Calculator

Estimate your basal metabolic rate — the calories you burn at complete rest — using the Mifflin-St Jeor equation.

BMR Calculator

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🔒 Nothing you enter is sent anywhere or stored. All processing happens in your browser.

How it works

Your basal metabolic rate (BMR) is the number of calories your body needs just to keep you alive at complete rest — powering your heart, brain, breathing and other essentials over 24 hours, with no activity at all. It's the foundation for understanding how many calories you actually use in a day.

This calculator uses the Mifflin-St Jeor equation, widely regarded as one of the most accurate for the general population. For men it is 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5; for women the final term is −161. Enter your details and the result updates instantly.

BMR alone doesn't account for movement. To estimate your full daily needs (your TDEE), multiply BMR by an activity factor — the calorie calculator does this for you. Everything here runs privately in your browser, so your health details are never uploaded.

Examples

30-year-old man, 175 cm, 70 kg → about 1,649 kcal/day at rest.
28-year-old woman, 162 cm, 60 kg → around 1,320 kcal/day.
Compare two weights to see how body mass shifts resting burn.

Frequently asked questions

What exactly is BMR?
It's the calories your body burns at complete rest over 24 hours to maintain basic functions like breathing and circulation, before any activity is added.
Which formula does this use?
The Mifflin-St Jeor equation, which is considered more accurate for most people than the older Harris-Benedict formula.
How is BMR different from TDEE?
BMR is your resting burn; TDEE is your total daily burn including activity. Multiply BMR by an activity factor to get TDEE — the calorie calculator does this.
Do I need body fat percentage?
No. Mifflin-St Jeor uses only weight, height, age and gender. Formulas like Katch-McArdle use body fat but require an accurate measurement.
Are my details saved?
No. The calculation runs entirely in your browser and nothing you enter is stored or uploaded.