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BMR Calculator

Estimate resting energy expenditure with the Mifflin-St Jeor equation. Online tools commonly label this result BMR.

1,780 cal/day

Predicted resting energy expenditure, shown as BMR.

Mifflin-St Jeor using weight, height, age, and sex equation path.
This is a resting prediction, not a full-day calorie target. Use a TDEE calculator to add activity.

What this BMR calculator predicts

Strict basal metabolic rate is measured under controlled conditions after rest and fasting. Resting energy expenditure, or REE, is measured under less restrictive conditions. International energy guidance treats these as related but distinct concepts.[1]

This tool uses the familiar public label “BMR,” but its equation was developed to predict REE.[2] It does not measure oxygen use, heat production, or metabolism in a laboratory.

Mifflin-St Jeor formula

Calculator method: For men, predicted REE is 10 x weight in kilograms + 6.25 x height in centimeters - 5 x age in years + 5. For women, the final constant is -161. Imperial entries are converted to kilograms and centimeters before the same equation is applied.

Example for a 32-year-old man at 82 kg and 178 cm:

(10 x 82) + (6.25 x 178) - (5 x 32) + 5 = 1,777.5 calories per day.

The displayed result is rounded. A correct calculation does not mean the prediction exactly matches that person's measured expenditure.

How to use the result

The result estimates energy use at rest. A normal day also includes food processing, walking, work, household movement, and exercise. Use the TDEE calculator when you need an initial maintenance estimate. Read TDEE vs BMR for a detailed comparison.

Do not treat predicted REE as a universal calorie floor or a prescribed intake. A daily target must consider total expenditure, the person's goal, and any relevant health or performance context.

Important limitations: Mifflin-St Jeor is a population prediction equation. Individual error remains possible because age, sex, height, and weight do not fully describe body composition or physiology. The equation may be less suitable during pregnancy, growth, illness, major weight change, or for people with medical conditions or unusual body composition.

Research sources

  1. Technical report FAO, WHO, and UNU. Human Energy Requirements, 2004. Read the definitions. Defines basal metabolic rate, resting metabolic rate, and total energy expenditure. Back to text
  2. Primary research Mifflin MD et al. A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition, 1990. DOI: 10.1093/ajcn/51.2.241. Original development paper for the equation used by this calculator. Back to text