BMR Calculator
Calculate your basal metabolic rate from sex, age, height and weight using the Harris-Benedict equation. For reference only.
A reference estimate; individual results vary.
How to use the BMR Calculator
- Choose Male or Female in the Sex list. The equation uses different constants for each.
- Fill in Age, Weight (kg) and Height (cm) as plain numbers, in metric units only.
- Press Calculate for the basal rate in kcal per day, rounded to a whole number.
The Harris-Benedict coefficients used here
For men the page starts at 66.47, adds 13.75 per kilogram and 5.0 per centimetre, then subtracts 6.75 per year of age; for women it starts at 655.1, adds 9.56 and 1.85, then subtracts 4.68. A 30-year-old of 170 cm and 65 kg gets 1,608 kcal as a man, 1,451 as a woman.
| Term | Male | Female |
|---|---|---|
| Base constant | 66.47 | 655.1 |
| Per kg of weight | +13.75 | +9.56 |
| Per cm of height | +5.0 | +1.85 |
| Per year of age | -6.75 | -4.68 |
Each extra year lowers the estimate by about 7 kcal for men, 5 for women.
Basal rate is not your daily calorie need
The figure covers only what the body spends at complete rest. Daily need is normally estimated by multiplying it by an activity factor, and this page has no field for activity, so that step is left to you.
Frequently asked questions
What is basal metabolic rate?
The energy your body uses at complete rest to keep basic functions running, such as breathing and circulation.
Does this include exercise?
No. This is the baseline figure. Your actual daily needs are higher and depend on how active you are.
Why is the gap between men and women so large?
Because the equation uses separate constants for each sex, and the weight and height multipliers are higher for men, so two people of the same size get different figures.
Can I switch to the Mifflin-St Jeor equation?
No. Harris-Benedict is the only equation here, and there is no option for body-fat-based formulas such as Katch-McArdle.