Enter your sex, age, height, and weight to calculate your Basal Metabolic Rate — the calories your body burns at complete rest.
How to Use the BMR Calculator
Pick a sex and a unit system before entering age, height, and weight — those two toggles change which formula variant and which fields get used underneath.
Lie perfectly still all day, eat nothing, and your body still burns calories — running your heart, keeping your organs going, maintaining body temperature. That baseline burn is basal metabolic rate, and it's usually the biggest single piece of anyone's daily energy budget.
Men: BMR = 10W + 6.25H − 5A + 5
Women: BMR = 10W + 6.25H − 5A − 161W is weight in kilograms, H height in centimeters, A age in years. This is the Mifflin-St Jeor equation, published by Mifflin, St Jeor, and colleagues in the American Journal of Clinical Nutrition in 1990, and since validated as more accurate for most people than the older Harris-Benedict formula it replaced — it's what registered dietitians tend to reach for first.
BMR on its own isn't a calorie target — it's the floor, before any activity gets added. That's what the TDEE calculator does next: takes this number and scales it up by how active a day actually looks.
An estimate, not a lab measurement. Indirect calorimetry is the only way to actually measure BMR — this formula gets close for most people but can miss meaningfully for those with unusual body composition, certain medical conditions, or on medications that affect metabolism.