BMR Calculator
Your basal metabolic rate plus maintenance calories by activity level.
Formula
About this calculator
Your Basal Metabolic Rate (BMR) is the number of calories your body burns just to stay alive at complete rest — powering your heart, brain, lungs and other organs. It is the single biggest component of your daily calorie needs, typically 60–70% of the total, which makes it the natural starting point for any weight-management plan.
This calculator uses the Mifflin-St Jeor equation, which most dietitians consider the most accurate for the general population. It takes your weight, height, age and sex and returns your resting calorie burn. From there it multiplies your BMR by standard activity factors — from sedentary (1.2) up to extra active (1.9) — to estimate your total maintenance calories: the amount that keeps your weight stable given how much you move.
To use the numbers, compare your intake with your maintenance figure. Eating below it creates the deficit needed to lose fat; eating above it supports weight or muscle gain. Because activity is estimated, treat the maintenance figures as a starting point, then adjust based on how your weight actually responds over two to three weeks.
Frequently asked questions
What is the difference between BMR and TDEE?
BMR is what you burn at complete rest. TDEE (total daily energy expenditure) is BMR multiplied by an activity factor to include movement, exercise and digestion — your real daily calorie need.
Which formula is used?
The Mifflin-St Jeor equation, widely regarded as more accurate for most people than the older Harris-Benedict equation.
How do I use my BMR to lose weight?
Find your maintenance calories for your activity level, then eat a moderate amount below that — a deficit of roughly 15–20% is sustainable for most people while preserving muscle.
Why does the estimate not match my tracker?
Activity factors are approximations and metabolism varies between individuals. Use the figure as a baseline and fine-tune it against your real weight trend over a few weeks.
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⚠️ Estimates are general guidance, not medical or dietary advice. Consult a qualified professional before making significant changes to your diet or exercise.