BMR Calculator

Estimate resting calorie expenditure with the Mifflin–St Jeor equation using age, height and weight.

Your calculation

For adults aged 19–78. Not for pregnancy, breastfeeding or clinical nutrition. These estimates are not a prescribed food intake.

kg
cm
years
Result

Estimated resting energy

1,649 kcal/day

Equation
Mifflin–St Jeor
Energy in kilojoules
6,898 kJ/day

The equation predicts resting energy expenditure (REE), often called BMR online. Actual needs vary with body composition, health and activity. Seek individual guidance from a qualified clinician or dietitian.

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How to use this calculator

Enter weight, height, age and the sex coefficient used by the equation. The result estimates energy spent at rest, before adding daily activity. For an activity-adjusted estimate, use the related Calorie Calculator.

The math behind it

Resting kcal/day = 10 × kg + 6.25 × cm − 5 × age + coefficient
Male coefficient: +5; female coefficient: −161
kJ/day = kcal/day × 4.184

A worked example

For 70 kg, 175 cm and age 30, the male equation gives 1,648.75 kcal/day and the female equation gives 1,482.75 kcal/day. Displayed estimates round to whole kcal.

Assumptions & precision

Mifflin–St Jeor (1990) predicts resting energy expenditure (REE), often labeled BMR online; it is not a laboratory BMR measurement. Ages 19–78 match the original study range. Weight 20–500 kg and height 100–250 cm are input limits, not validation of accuracy at all extremes. The original equation has male/female coefficients and does not model hormone therapy or individual body composition. Not for pregnancy, breastfeeding, children or clinical nutrition. Resting expenditure is not a minimum-food-intake recommendation.

A common question

Is BMR how many calories I should eat?

No. Resting expenditure excludes much of daily activity. Your total needs and an appropriate eating plan depend on more than this equation. Consult a qualified clinician or dietitian for individual guidance.