Metric example
For a 30-year-old male at 75 kg and 180 cm, Mifflin–St Jeor gives: 10 × 75 + 6.25 × 180 − 5 × 30 + 5 = 1,730 kcal/day.
Estimate adult basal metabolic rate with Mifflin–St Jeor or revised Harris–Benedict, using metric or US customary measurements.
Basal metabolic rate estimates how much energy your body uses over 24 hours to maintain essential functions such as breathing, circulation, and temperature regulation while at rest. Equation-based BMR is an estimate rather than a direct laboratory measurement.
BMR represents resting energy only. Total daily energy expenditure also includes daily movement, exercise, and the thermic effect of food. A BMR result should therefore not be treated as a daily calorie target or nutrition prescription.
CalcRocket uses this equation by default.
Male: 10W + 6.25H − 5A + 5 · Female: 10W + 6.25H − 5A − 161Male: 88.362 + 13.397W + 4.799H − 5.677A · Female: 447.593 + 9.247W + 3.098H − 4.330AThe equations were developed from different research populations and use different coefficients. Mifflin–St Jeor is a commonly used modern default, while revised Harris–Benedict is useful as a comparison. Neither formula accounts directly for individual body composition or provides an exact measurement.
For a 30-year-old male at 75 kg and 180 cm, Mifflin–St Jeor gives: 10 × 75 + 6.25 × 180 − 5 × 30 + 5 = 1,730 kcal/day.
For a 30-year-old male at 5 ft 10 in and 165 lb, the measurements convert to approximately 177.8 cm and 74.8 kg before the selected metric equation is applied.
BMR is an estimate, not a direct measurement. Actual energy needs vary, and BMR is not the same as total daily calorie needs.
This calculator is intended for adults. Pregnancy, breastfeeding, illness, body composition, medications, and other factors may affect energy needs. Consult a qualified healthcare professional for personalized medical or nutrition advice.
Basal metabolic rate is an estimate of the energy your body uses over 24 hours to support basic functions while at rest.
This calculator applies either the Mifflin–St Jeor or revised Harris–Benedict equation to age, height, weight, and the sex term specified by the selected formula.
Mifflin–St Jeor is commonly used as a modern default, but neither equation is exact for every person. Direct measurement is needed for an individualized value.
BMR estimates energy use at rest. Total daily energy expenditure, or TDEE, also includes movement, exercise, and the energy used to digest food.
BMR can be one starting point for estimating daily needs, but it is not itself a calorie target and must be adjusted for activity and individual circumstances.
These historical population equations include male and female constants because those variables improved their statistical estimates. They cannot capture each person’s body composition or physiology.
They are related estimates but use different testing conditions. Resting metabolic rate is generally measured under less restrictive conditions and may be slightly higher.
No. This calculator is intended for adults ages 18 to 120. Children need age-appropriate assessment from a qualified professional.
Equation results are estimates. Pregnancy, breastfeeding, illness, medications, body composition, and other individual factors can change actual energy use.