How it works
Basal metabolic rate (BMR) is the energy your body uses at complete rest to keep you alive: breathing, circulation, temperature and cell repair. For most people it is the largest share of daily calorie use.
The Mifflin-St Jeor equation (1990) is the one most dietitians use today because it tracks measured values more closely than older formulas. The revised Harris-Benedict equation (Roza and Shizgal, 1984) is shown alongside for comparison.
Both equations predict an average for people of your size, age and sex; individual metabolism can differ by 10% or more. Results are estimates, not medical advice.
Formula
Mifflin-St Jeor: BMR = 10 × kg + 6.25 × cm − 5 × age + 5 (men) or − 161 (women)
Questions people ask
What is the difference between BMR and TDEE?
BMR is calories burned at total rest. TDEE (total daily energy expenditure) adds everything else: digestion, daily movement and exercise. TDEE is BMR multiplied by an activity factor, typically 1.2 to 1.9.
Which BMR formula is most accurate?
Studies comparing equations against measured metabolic rate generally find Mifflin-St Jeor the most reliable for healthy adults, usually within about 10% for most people. Harris-Benedict tends to read slightly higher.
Does muscle increase BMR?
Yes, lean tissue uses more energy at rest than fat tissue, though the effect is modest, roughly 6 kcal per pound of muscle per day. Equations based on lean mass, like Katch-McArdle, account for this directly.