BMR Calculator
Calories burned at complete rest — the Mifflin–St Jeor standard.
How this is calculated
BMR = 10×kg + 6.25×cm − 5×age + (male: +5 · female: −161)
Worked example: male, 30, 80 kg, 180 cm → 800 + 1,125 − 150 + 5 = 1,780 kcal/day — about 74 kcal every hour, awake or asleep. To turn BMR into a daily eating target, multiply by an activity factor on the TDEE calculator; eating at BMR itself is a heavy deficit, not maintenance. Estimates, not medical advice.
Frequently asked questions
What is BMR exactly?
Basal metabolic rate: the energy your body burns at complete rest just to run organs, temperature, and repair — typically 60–75% of everything you burn in a day. It is the floor of your energy budget, not a target to eat at.
Which BMR formula does this use?
Mifflin–St Jeor (1990), the one clinical dietetics standardized on after it out-predicted the older Harris–Benedict equation in validation studies. The formula is printed under the calculator with a worked example.
Should I eat at my BMR to lose weight?
No — that is the most common misuse of this number. You burn well above BMR just by living (see the TDEE calculator). Sustainable deficits subtract from TDEE, not BMR; eating at BMR is usually an aggressive, hard-to-hold cut.
Why is my BMR lower than my friend’s?
Mass, height, age, and sex drive the equation — more body, more burn. Beyond the formula, muscle tissue burns more at rest than fat, which the equation cannot see; two people with identical stats can differ by a few percent either way.