BMR Calculator
The calories your body burns at complete rest — the baseline behind everything else.
That is what you'd burn in bed all day — roughly 60–70% of your total daily burn. Real life adds walking, work, and exercise on top: your TDEE. The Calorie / TDEE Calculator multiplies your BMR by your activity level and turns it into daily calorie targets for losing, maintaining, or gaining weight.
Estimates for education — not medical advice. Talk to a healthcare professional before making big changes to your diet or training.
How to calculate your BMR
- Pick your units — metric or imperial.
- Enter your age, sex, height, and weight. Morning weight is the most consistent.
- Press Calculate BMR. The Mifflin-St Jeor result appears, with the revised Harris-Benedict equation as a comparison line.
- Use it as a baseline. BMR is rest-only — for real-world calorie targets, feed it into the Calorie / TDEE Calculator.
Frequently asked questions
What is BMR?
Basal metabolic rate: the calories your body burns at complete rest in 24 hours — just keeping you alive (breathing, circulation, cell repair). It is usually 60–70% of your total daily burn.
How is BMR calculated?
This calculator uses the Mifflin-St Jeor equation, the most widely used BMR formula: for men 10×kg + 6.25×cm − 5×age + 5, for women the same minus 161 instead of plus 5.
What is the difference between BMR and TDEE?
BMR is rest-only burn; TDEE (total daily energy expenditure) is BMR plus everything else — walking, work, exercise, digestion. TDEE is the number that matters for weight loss; our calorie calculator derives it from your BMR.
How accurate is a BMR calculator?
Good estimates are usually within about 10% of lab-measured BMR. Accuracy drops for very muscular, very lean, or older people, since the formulas use weight rather than muscle mass.
Is this medical advice?
No. These are estimates for education only — not medical advice. Talk to a healthcare professional before making big changes to your diet or training.
More from the codex
BMR Calculator
Your resting burn: basal metabolic rate, explained.
Calorie / TDEE Calculator
Your daily calorie target for losing, maintaining, or gaining weight.
Open tool → LiveBody Fat Calculator
U.S. Navy tape-method estimate of your body fat percentage.
Open tool → LiveBMI Calculator
BMI, WHO category gauge, and healthy weight range.
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