BMR Calculator
Calculates Basal Metabolic Rate using the Mifflin-St Jeor equation with age, sex, height, and weight. Nutritionists use it for diet planning. Health data never leaves your device — every calculation runs locally in your browser.
How to Use the BMR Calculator
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Frequently Asked Questions
What is BMR?
Basal Metabolic Rate — calories your body burns at complete rest in 24h. Example: a 30-year-old man, 178cm, 75kg → ≈1,718 kcal/day (10×75 + 6.25×178 − 5×30 + 5). Everything above that (movement, digestion, exercise) adds on top. Defaults (male, 25, 70 kg, 170 cm, sedentary) give BMR ≈1,643 and TDEE ≈1,971.
Mifflin-St Jeor vs Harris-Benedict?
Mifflin-St Jeor (men: 10w + 6.25h − 5a + 5; women: −161 instead of +5) validates better against modern calorimetry, underestimating less for overweight users. This tool uses Mifflin-St Jeor.
BMR vs TDEE — which do I diet on?
Never eat at BMR long-term — that is starvation level. Multiply BMR by activity (sedentary 1.2 … very active 1.9) to get TDEE, then subtract 300–500 kcal for fat loss. Use the calorie calculator for the full chain.
Does muscle raise BMR?
Yes, ~6 kcal/lb/day vs ~2 for fat — but the effect is modest: 5kg of extra muscle adds roughly 60–70 kcal/day. Strength training matters more for the calories it burns directly.
When using BMR Calculator, is my health data stored?
No. All calculations run locally in your browser. No health data is transmitted or stored.
Related Health Tools
TDEE Calculator
Calculate your Total Daily Energy Expenditure (TDEE) from BMR and activity level. Find how many calories you burn per day.
Daily Calorie Needs
Calculate your daily calorie needs from BMR (Mifflin-St Jeor) times activity level. Shows basal burn plus maintenance calories for fitness planning. Health data never leaves your device — every calculation runs locally in your browser.
Last updated October 2026