BMR Calculator
Basal metabolic rate is the energy your body spends staying alive while you do nothing at all. The number is easy to compute and easy to misuse, because it is deliberately lower than anything you would ever eat.
Basal metabolic rate
1,648.75
- The weight, height and age terms before the constant
- 1,643.75
- Daily needs if sedentary
- 1,978.5
- Daily needs with moderate exercise
- 2,555.5625
- Daily needs with hard daily exercise
- 2,844.0938
Values update as you type. This calculator covers the single scenario its formula assumes — see Common Mistakes for what it leaves out.
The formula this calculator uses
BMR = 10w + 6.25h - 5a + s
- w
- Body weight in kilograms
- h
- Height in centimetres
- a
- Age in years
- s
- Sex constant — plus 5 for a male, minus 161 for a female
How to check the result by hand
- 1
Convert everything to kilograms and centimetres
The coefficients assume metric units, so a weight in pounds and a height in inches must be converted first. One pound is 0.453592 kilograms and one inch is 2.54 centimetres; converting after the calculation, or not at all, is the fastest route to an answer that is confidently wrong.
- 2
Compute the three variable terms
Multiply weight by 10, height by 6.25 and age by 5. For 70 kg, 175 cm and 30 years that gives 700, 1093.75 and 150. Keep the decimals rather than rounding, because the terms are added together and early rounding compounds.
- 3
Add the sex constant
Subtract the age term and then add the constant: plus 5 for a male, minus 161 for a female. The three terms come to 1643.75, so the male estimate is 1648.75 and the female estimate 1482.75 — a 166 kcal gap from the constant alone.
- 4
Scale to daily needs with an activity factor
Multiply the BMR by a factor between 1.2 and 1.9 to reach total daily expenditure. The default case gives 1978.5 sedentary, 2267.03125 light, 2555.5625 moderate, 2844.09375 hard and 3132.625 for an athlete. This is the figure to compare against food intake.
- 5
Sanity-check against expectations
Most adults land between about 1200 and 2000 kcal for BMR, with larger and younger bodies at the top. A result far outside that band usually means a unit error, a misplaced sex constant or a decimal slip. Recomputing the three terms separately localises the mistake quickly.
For worked examples, common mistakes and the limits of this formula, read the full How To Calculate BMR page.