BMR Calculator

Your Basal Metabolic Rate is the energy your body spends just existing — heart beating, lungs breathing, brain thinking, cells repairing — measured with you at complete rest. It's typically 60–70% of everything you burn in a day, which makes it the foundation number for any calorie planning: every diet calculation starts from BMR.

This calculator uses the Mifflin-St Jeor equation, published in 1990 and identified by the American Dietetic Association's review as the most accurate of the standard formulas for modern populations — it superseded the older Harris-Benedict equation most casual calculators still use. Enter age, sex, height and weight in metric or imperial and the estimate is instant.

What the number means in practice: you cannot sustainably eat below your BMR for long — it's the energy cost of staying alive — and your real daily need is BMR multiplied by an activity factor. That next step is exactly what the Calorie Calculator on this site does; the two tools are designed as a pair. As with all formula-based estimates, individual metabolism varies a few percent either way, so treat the output as a well-grounded starting point rather than a lab measurement.