BMR Calculator (Basal Metabolic Rate)
Basal metabolic rate (BMR) is the energy your body uses at complete rest for breathing, circulation and cell renewal — typically 60–70% of everything you burn in a day. This tool computes it with two published equations: Mifflin-St Jeor (1990), the current clinical standard, and the revised Harris-Benedict equation for comparison. Multiply your BMR by an activity factor — or use the calorie (TDEE) calculator — to estimate total daily needs. This tool is for information only and is not medical advice.
Frequently asked questions
What is the difference between BMR and TDEE?
BMR is the energy burned at complete rest, while TDEE (total daily energy expenditure) adds everything else — daily movement, exercise and digestion. TDEE is estimated by multiplying BMR by an activity factor between 1.2 and 1.9.
Which BMR formula is the most accurate?
Validation studies found the Mifflin-St Jeor equation closest to measured resting energy expenditure in most adults, which is why it has replaced the older Harris-Benedict equation in clinical practice. Both are shown here for comparison.
Can I increase my BMR?
Muscle tissue burns more energy at rest than fat, so building muscle through resistance training raises BMR somewhat. Severe calorie restriction works the other way — the body adapts by lowering its resting expenditure.