BMR Calculator
What is BMR?
Your Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest - the energy your heart, brain, lungs and other organs need just to keep you alive. It is the largest piece of your daily calorie burn, usually 60-75% of the total.
This calculator uses the Mifflin-St Jeor equation, the most widely recommended formula in clinical settings, to estimate your BMR from age, gender, height and weight. Knowing your BMR is the foundation for setting calorie targets - your actual daily burn is higher once activity is added.
Frequently Asked Questions
What is the Mifflin-St Jeor equation?
For men: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age + 5. For women: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age - 161. It estimates resting energy expenditure more accurately than older formulas like Harris-Benedict.
What is the difference between BMR and RMR?
BMR is measured under strict conditions (fasting, at rest, in a controlled environment). RMR (resting metabolic rate) is measured under less strict conditions and is usually slightly higher. Both are estimates of resting energy use; for practical purposes the difference is small.
How do I use my BMR to lose weight?
Your daily burn (TDEE) is your BMR times an activity factor, typically 1.2-1.9. To lose about 0.5 kg per week, eat roughly 500 calories below your TDEE - but do not chronically eat below your BMR, which can slow your metabolism.