BMR Calculator
Estimate your Basal Metabolic Rate — the calories your body burns at rest just to keep you alive. Uses the Mifflin-St Jeor equation, the modern standard.
Your details
How to use this calculator
1. Pick sex and units
BMR formulas differ slightly between male and female. The unit toggle switches between metric (kg/cm) and imperial (lb/ft·in).
2. Enter age, weight, and height
Use current measurements. BMR shifts with age (lower) and with body composition (more muscle = higher BMR).
3. Read the result
The main number is your BMR — calories burned at complete rest over 24 hours. The grid shows TDEE estimates (BMR × activity factor) for different lifestyles.
4. Use it to plan calories
To maintain weight, eat near your TDEE. To lose weight, aim for a 300-500 kcal/day deficit. To gain, add 300-500 kcal/day surplus. Adjust based on weekly weight trends.
About BMR & the formula
The Mifflin-St Jeor equation
BMR (male) = 10 × kg + 6.25 × cm − 5 × age + 5
BMR (female) = 10 × kg + 6.25 × cm − 5 × age − 161
This equation, published in 1990, replaced the older Harris-Benedict as the modern standard because it more accurately predicts BMR for both lean and obese adults.
BMR vs. TDEE
BMR is the energy at total rest. TDEE (Total Daily Energy Expenditure) is BMR × an activity factor that accounts for movement, exercise, and the thermic effect of food.
Accuracy caveats
BMR estimates are within ~10% of the true value for most adults. Body composition matters: very muscular people burn more than the formula predicts. For precise numbers, indirect calorimetry at a clinic is the gold standard.