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BMR calculator: your resting calorie burn

Short answer

Basal metabolic rate (BMR) is the energy your body uses at complete rest. The Mifflin–St Jeor equation is 10 × weight (kg) + 6.25 × height (cm) − 5 × age, plus 5 for men or minus 161 for women. For a 30-year-old man who is 180 cm and 80 kg, that is 1,780 kcal a day; the revised Harris–Benedict equation gives 1,854 kcal.

Last reviewed 28 October 20262 published sourcesNot medical advice

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BMR calculator

Resting calories from two published equations.

Units
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years
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Enter your age, weight and height to see your BMR.

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The two equations

Mifflin–St Jeor (1990): 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) + 5 for men, or − 161 for women. It came from 498 people aged 19–78, measured by indirect calorimetry (Mifflin et al., 1990).

Harris–Benedict, revised by Roza and Shizgal (1984): men 88.362 + 13.397 × weight + 4.799 × height − 5.677 × age; women 447.593 + 9.247 × weight + 3.098 × height − 4.330 × age (Roza & Shizgal, 1984). The table below compares the two.

BMR by equation (kcal/day)
PersonMifflin–St JeorHarris–Benedict (revised)
Woman, 25, 163 cm, 58 kg1,3131,381
Woman, 45, 168 cm, 72 kg1,3841,439
Woman, 65, 160 cm, 68 kg1,1941,291
Man, 25, 178 cm, 75 kg1,7431,805
Man, 45, 180 cm, 88 kg1,7851,876
Man, 65, 175 cm, 82 kg1,5941,658
Rounded to the nearest kcal.

What moves your BMR

Size matters most: bigger bodies burn more at rest. In Mifflin's data, fat-free mass was the best single predictor of resting energy (Mifflin et al., 1990), which is why two people with the same weight can differ. Age lowers the estimate by 5 kcal a year in the Mifflin–St Jeor equation.

For the calories you burn across a whole day, see the TDEE calculator. To split a calorie target into protein, carbs and fat, use the macro calculator.

Your resting burn is only the start

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Common questions

What is the most accurate BMR formula?

Mifflin et al. built their equation in 1990 from measured resting energy in 498 healthy adults, both normal weight and obese, and found the original 1919 Harris–Benedict equations overestimated measured values by 5%. Every prediction equation can still be off for an individual; only indirect calorimetry measures it.

What is the difference between BMR and RMR?

Basal metabolic rate is measured under strict conditions: just woken, fasted and lying still. Resting metabolic rate or resting energy expenditure is measured at rest under looser conditions and runs slightly higher. The Mifflin–St Jeor equation predicts resting energy expenditure; most calculators, this one included, use it as a practical BMR.

How do I get from BMR to daily calories?

Multiply BMR by a physical activity level. FAO/WHO/UNU bands run from 1.40–1.69 for a sedentary or light lifestyle up to 2.00–2.40 for a vigorously active one. The TDEE calculator does this step for you.

Sources

Figures on this page were checked against these publications on 28 October 2026.

  1. Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition. 1990;51(2):241–247. doi.org/10.1093/ajcn/51.2.241
  2. Roza AM, Shizgal HM. The Harris Benedict equation reevaluated: resting energy requirements and the body cell mass. American Journal of Clinical Nutrition. 1984;40(1):168–182. doi.org/10.1093/ajcn/40.1.168

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