BMR Calculator
Calculate your Basal Metabolic Rate (BMR) — the calories your body burns at complete rest.
About the BMR Calculator
Basal Metabolic Rate is the number of calories your body burns just to stay alive at complete rest — breathing, circulating blood, maintaining organ function — before any movement or digestion is factored in. This calculator computes BMR using the Mifflin-St Jeor equation, one of the most accurate and widely validated formulas available.
How It Works
The calculator plugs your weight in kilograms, height in centimeters, age, and sex into the Mifflin-St Jeor formula, which was developed from measured metabolic data and adjusts differently for male and female bodies to reflect typical differences in body composition.
BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + (5 if male, −161 if female).
Example
Scenario: A 30-year-old male weighing 70 kg and 175 cm tall.
Result: BMR of about 1,649 kcal per day at complete rest.
Assumptions & Limitations
- Uses the Mifflin-St Jeor equation, generally considered more accurate for most adults than the older Harris-Benedict formula.
- Assumes typical body composition for the given sex — very muscular or very high body-fat individuals may see somewhat different real BMR.
- BMR does not account for activity — use the TDEE Calculator to estimate total daily calorie burn including movement and exercise.
- Formula-based BMR is an estimate; direct metabolic testing is more accurate for individuals with unusual body composition.