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BMR Calculator

Your basal metabolic rate is the energy your body uses in a day at complete rest — breathing, circulation, keeping warm. Enter your sex, age, height and weight to estimate it with the Mifflin-St Jeor equation, with the revised Harris-Benedict result shown for comparison.

Quick examples
years

Adults 18 and over.

ft
in
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BMR (Mifflin-St Jeor)1,783 kcal/day
BMR (revised Harris-Benedict)
1,865 kcal/day
Per hour at rest
74.3 kcal

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      Formula

      Mifflin-St Jeor, men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
      Mifflin-St Jeor, women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
      Revised Harris-Benedict, men: 88.362 + 13.397 × kg + 4.799 × cm − 5.677 × age
      Revised Harris-Benedict, women: 447.593 + 9.247 × kg + 3.098 × cm − 4.330 × age

      How to use it

      1. Select your sex and enter your age.
      2. Enter your height and weight in the units you prefer.
      3. Read your BMR in calories per day. Multiply by an activity factor — or use the TDEE calculator — to get the calories you actually burn.

      Worked examples

      A 30-year-old man, 5 ft 10 in and 180 lb

      BMR (Mifflin-St Jeor)
      1,783 kcal/day
      BMR (revised Harris-Benedict)
      1,865 kcal/day
      Per hour at rest
      74.3 kcal

      A 35-year-old woman, 165 cm and 65 kg

      BMR (Mifflin-St Jeor)
      1,345 kcal/day
      BMR (revised Harris-Benedict)
      1,408 kcal/day
      Per hour at rest
      56.1 kcal

      Which equation to trust

      Mifflin-St Jeor was published in 1990 and is the equation most often recommended for healthy adults today. Harris-Benedict dates from 1919 and was revised by Roza and Shizgal in 1984; it usually comes out a little higher. Both are population averages, and an individual’s measured rate commonly differs by 10% or so either way.

      Neither equation knows your body composition. Two people of the same height, weight and age will get the same answer even if one carries far more muscle, and muscle burns more energy at rest than fat does.

      This is an estimate for general information, not medical advice. Talk to a doctor or other qualified clinician before making health decisions based on it.

      Questions people ask

      What is a normal BMR?

      It depends on size, age and sex. A 30-year-old man who is 5 ft 10 in and 180 lb comes out at about 1,783 kcal a day; a 35-year-old woman who is 165 cm and 65 kg at about 1,345 kcal.

      Is BMR the number of calories I should eat?

      No. BMR covers only rest. Daily needs are BMR multiplied by an activity factor of roughly 1.2 to 1.9, so most people burn several hundred calories more than their BMR.

      What is the difference between BMR and RMR?

      BMR is measured under strict conditions — fasted, rested and lying still. Resting metabolic rate is measured more loosely and tends to be slightly higher. In everyday use the two terms are treated as the same thing.

      Related calculators

      TDEE CalculatorTotal calories you burn in a day: BMR × your activity level.Calorie CalculatorDaily calories to maintain, lose or gain weight.Calorie Deficit CalculatorThe daily deficit and calorie target to reach a goal weight by a set date.Lean Body Mass CalculatorLean body mass from height and weight, by the Boer formula.BMI CalculatorBody mass index, its WHO category and the healthy weight range for your height.