BMR Calculator (Basal Metabolic Rate)

What this BMR estimate represents

This BMR calculator estimates daily resting energy from age, height, weight, and the male or female option used by the equation. The page labels the result BMR, but the Mifflin–St Jeor equation was developed to predict resting energy expenditure (REE). It is an estimate from body measurements, not a direct measurement of your metabolism. The result is shown as a rounded whole number in kilocalories per day (kcal/day).

The equation uses kilograms, centimeters, and years. For U.S. customary entries, pounds and inches are converted to kilograms and centimeters before calculation:

For example, at age 30, 175 cm, and 70 kg, the male equation gives 1,648.75, displayed as 1,649 kcal/day. With the same measurements and the female equation, it gives 1,482.75, displayed as 1,483 kcal/day. The different constants are part of the published prediction equations; they do not measure an individual’s body composition.

The original 1990 study derived the prediction from 498 healthy adults, ages 19 to 78, and measured REE using indirect calorimetry. Its findings support the equation and study scope, not a guarantee that an estimate matches any one person’s measured needs.

Enter measurements in the selected units

1. Choose metric or imperial

   Metric uses kilograms and centimeters. Imperial uses pounds and inches; enter height as total inches, such as 69 for 5 ft 9 in. Changing the unit system clears age, height, and weight, so re-enter those values after switching.

2. Select the equation option

   Choose male or female. These options select the corresponding constant in the Mifflin–St Jeor equation.

3. Fill in age, height, and weight

   Use positive numeric values and follow the unit labels. A result appears once all three entries are valid. Decimal measurements are accepted.

4. Read or copy the estimate

   The result is a rounded kcal/day estimate. Reset clears the three measurements while keeping the selected units and equation option.

Common questions about a BMR result

Limits to keep in mind

This is a general equation-based estimate, not a metabolic test, diagnosis, prescription, or personalized nutrition plan.

• The result is not a minimum safe food intake, a daily calorie allowance, or a measure of calories burned through exercise and everyday activity. Do not use it alone to set a diet target.
• The original equation was developed using healthy adults aged 19–78. It may not represent children, adolescents, pregnancy or breastfeeding, illness, hospitalization, or people whose circumstances differ substantially from that study population.
• Age, height, and weight do not capture every factor that can affect an individual’s energy expenditure. If you need guidance for a health condition or a nutrition plan, discuss an appropriate assessment with a qualified health professional.