BMR Calculator
Find your Basal Metabolic Rate — the calories your body burns at complete rest — with the Mifflin-St Jeor equation.
How it works
BMR = 10×kg + 6.25×cm − 5×age + 5 (men) / − 161 (women)
The Mifflin-St Jeor equation, which validation studies found closest to measured metabolic rates for most adults. It estimates the energy your body uses for basic functions — breathing, circulation, cell repair — before any movement.
Worked example
A 30-year-old man, 5′9″ (175.3 cm), 170 lb (77.1 kg): BMR = 10×77.1 + 6.25×175.3 − 5×30 + 5 = 1,722 kcal/day.
Frequently asked questions
BMR vs TDEE — what’s the difference?
BMR is rest-only burn. TDEE multiplies it by your activity level to estimate real daily burn — the number diet planning actually uses.
Can I eat below my BMR?
Sustained intakes far below BMR are hard to maintain and can cost muscle and nutrients. Most guidance sets deficits from TDEE, not BMR, and keeps them moderate.
Why do results differ between BMR calculators?
Different equations (Harris-Benedict, Katch-McArdle, Mifflin-St Jeor) give slightly different numbers. All are estimates within roughly ±10%.
Related calculators
This is a general educational estimate, not medical advice. Bodies differ — for decisions about diet, training, medication or health conditions, talk to a doctor or registered dietitian.