BMR Calculator

Basal metabolic rate (BMR) is the energy your body needs in a day if you did nothing but rest: to keep your heart beating, lungs breathing, brain working and temperature steady. For most people it's 60–70% of the calories they burn each day.

This calculator estimates BMR from your sex, age, height and weight with the Mifflin–St Jeor equation, or the revised Harris–Benedict and Katch–McArdle formulas if you prefer. It also multiplies your BMR by an activity factor to show your total daily energy expenditure, and gives calorie targets for losing, keeping or gaining weight.

Mifflin–St Jeor (1990) is the formula most dietitians use, because it has proved the most accurate for most adults in studies. The revised Harris–Benedict equation (Roza and Shizgal, 1984) is older and tends to give slightly higher numbers. Katch–McArdle uses lean body mass instead of sex and age, which makes it better for very muscular people, if you have a reliable body fat figure.

BMR falls slowly with age and rises with muscle, which is one reason strength training helps with long-term weight control.