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The Mifflin–St Jeor equation: estimating resting energy

Learn the Mifflin–St Jeor equations, work through an example and convert resting energy into an estimated TDEE.

By Calculadoras.Tools Published 5 min read

The Mifflin–St Jeor equation estimates resting energy expenditure from weight, height, age and sex. In common calculator terminology, the result is often labelled BMR.

With weight in kilograms, height in centimetres and age in years:

Men:    10W + 6.25H - 5A + 5
Women:  10W + 6.25H - 5A - 161

For a 30-year-old woman weighing 65 kg and measuring 165 cm:

10(65) + 6.25(165) - 5(30) - 161
= 1,370 kcal/day approximately

That is a resting estimate, not maintenance calories. To approximate total daily energy expenditure, multiply it by an activity factor:

TDEE = resting estimate x activity factor

An activity factor of 1.55 would produce about 2,124 kcal/day. The factor is often the largest source of uncertainty.

The original equation was developed from measured resting expenditure in 498 adults. Like every population equation, it can differ from an individual’s measured metabolism, particularly when body composition or health differs from the study population. Use the TDEE calculator as a starting point and refine it with real trends.

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