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BMR Calculator
Your basal metabolic rate is the energy your body burns at complete rest — the floor beneath every calorie plan.
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Understanding Your BMR
Your BMR is roughly 60-75% of the calories you burn each day. The rest comes from physical activity and the thermic effect of food.
- Muscle mass raises BMR — strength training and protein help keep it high while dieting.
- BMR slowly declines with age; recalculate every few years.
- Never eat below roughly your BMR long-term without medical supervision.
Frequently Asked Questions
What is the difference between BMR and TDEE?
BMR is calories at complete rest. TDEE (total daily energy expenditure) adds activity — multiply BMR by your activity factor to get TDEE.
Which equation should I use?
Mifflin-St Jeor is the modern default. Harris-Benedict is shown for comparison; the two usually differ by a few percent.
Why is my BMR lower than my friend's?
Sex, age, height, weight and muscle mass all matter. Larger bodies and more muscle burn more at rest.
Should I eat below my BMR to lose weight?
Generally no. A moderate deficit above BMR (500 kcal below maintenance) is safer and easier to sustain.
Practical Example
A 40-year-old woman, 65 kg, 165 cm:
- Mifflin-St Jeor BMR ≈ 1,390 kcal/day
- Harris-Benedict ≈ 1,420 kcal/day (for comparison)
- With light activity (×1.375), her TDEE ≈ 1,910 kcal/day
What Your Results Mean
- BMR — calories burned at complete rest; your baseline energy need.
- TDEE — BMR × activity factor; your real daily maintenance calories.
- Use TDEE as your reference point for weight changes, not BMR alone.
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