BMR Calculator

Basal metabolic rate is what you burn doing nothing at all — breathing, circulation, keeping warm. It is the floor under every calorie target, and eating below it for long is how people stall. This calculator uses the Mifflin-St Jeor equation, the most accurate formula validated for modern populations.

How BMR is calculated

• Men: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age) + 5
• Women: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age) - 161
• The Mifflin-St Jeor equation is more accurate than the older Harris-Benedict formula
• BMR accounts for sex, age, height and weight — not activity level

What to do with your BMR

• Multiply by an activity factor to get your TDEE (total daily energy expenditure)
• Your TDEE is the starting point for setting a calorie target
• A 500 calorie daily deficit below TDEE produces roughly 0.5 kg of fat loss per week
• Never eat significantly below your BMR long-term — it triggers muscle loss and metabolic adaptation