BMR and Calorie Calculator
Estimate the calories your body burns at rest and in a normal day.
Good to know. Most of the energy you burn goes on simply staying alive. Exercise is the smaller part.
Not medical advice. A general estimate for healthy adults.
How it works
In plain words
The Mifflin-St Jeor equation estimates resting energy from weight, height, age and sex. Multiply it by an activity factor to estimate what you burn in a typical day.
The formula
men: BMR = 10 × kg + 6.25 × cm − 5 × age + 5 women: BMR = 10 × kg + 6.25 × cm − 5 × age − 161 daily needs = BMR × activity factor (1.2 to 1.9)
Worked example
A 35-year-old woman, 65 kg and 165 cm: 650 + 1,031.25 − 175 − 161 = 1,345 kcal a day at rest. With light exercise, about 1,850 kcal a day.
Sources
Sources checked September 29, 2026. 4 automated tests check its answers on every change.
About the BMR and calorie calculator
Your basal metabolic rate (BMR) is the energy your body uses just to stay alive at rest: breathing, circulating blood, keeping warm. For most people, it is the largest part of the calories they burn each day.
This calculator uses the Mifflin-St Jeor equation, which research has found to be among the most accurate simple formulas for healthy adults. It is based on weight, height, age and sex. Multiplying the BMR by an activity factor gives an estimate of your total daily energy expenditure, sometimes called maintenance calories.
Treat the result as a starting point. Individual metabolism varies, and two people with the same numbers can burn noticeably different amounts. The activity levels are rough, and most people overestimate how active they are. If you are tracking your weight, adjust based on what actually happens over a few weeks.
These equations are designed for adults. They are not suitable for children, during pregnancy or breastfeeding, or for people with certain medical conditions. Very low-calorie diets can be harmful, so talk to a doctor or registered dietitian before making big changes.
Questions people ask
What is BMR?
Basal metabolic rate: the calories your body burns at complete rest to keep basic functions going.
What is the difference between BMR and daily calorie needs?
BMR is energy at rest. Daily needs (TDEE) add movement and exercise, estimated by multiplying BMR by an activity factor.
How accurate is the Mifflin-St Jeor equation?
For most healthy adults, it predicts resting energy within about 10%. Individual results vary.
Why does the calculator ask for sex?
Because the equation was derived from measurements that differ on average between males and females, mainly due to body composition.