Resting Metabolic Rate (Mifflin) Calculator

About this calculator

This calculator uses the Mifflin-St Jeor equation, published in 1990 and now the formula most dietitians consider the most accurate for estimating resting metabolic rate in the general population: for men, RMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5; for women, the same terms minus 161 instead of plus 5. It replaced the older Harris-Benedict equation after studies showed it more closely matched measured energy expenditure, especially in people with overweight or obesity.

Dietitians and fitness coaches use the result as the baseline for a calorie target: multiplying RMR by an activity factor gives total daily energy expenditure, from which a calorie deficit or surplus is planned for weight loss or muscle gain.