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How to use
Estimate basal metabolic rate using the calculator's stated equation.
- Enter age, weight and height, then choose the sex used in the equation.
- Check units.
- Use the result as an estimate.
How it is calculated
Example
Example: for a 30-year-old male weighing 70 kg and 175 cm tall, the estimate is about 1,649 kcal/day at basal rest.
Important notes
BMR is a mathematical estimate, not a direct measurement or dietary prescription.
Worked examples and interpreting results
For age 30, weight 70 kg and height 170 cm, the Mifflin equation gives 1617.5 kcal/day with the male formula and 1451.5 with the female formula.
| Case | Calculation | Result |
|---|---|---|
| Male formula | 10 × 70 + 6.25 × 170 − 5 × 30 + 5 | 1,617.5 kcal/d |
| Female formula | 10 × 70 + 6.25 × 170 − 5 × 30 − 161 | 1,451.5 kcal/d |
How to check the result
This estimates resting energy, not total daily expenditure or a personal dietary target. The calculator displays whole numbers, so rounding may show 1618 or 1452.
BMR calculator explained: resting calories versus daily needs
The Mifflin–St Jeor estimate combines adult weight in kilograms, height in centimetres and age with its sex-specific equation. The result approximates resting energy expenditure and is not a complete daily calorie target.
- Man: 70 kg, 175 cm, age 30: 10×70 + 6.25×175 − 5×30 + 5 = 1648.75 kcal/day
- Woman with identical measurements: 10×70 + 6.25×175 − 5×30 − 161 = 1482.75 kcal/day
- Woman: 60 kg, 165 cm, age 25: 10×60 + 6.25×165 − 5×25 − 161 = 1345.25 kcal/day
Important distinction
BMR formulas estimate population averages rather than measuring an individual's metabolism. They do not account fully for illness, pregnancy or exercise; do not use a single estimate as medical guidance.