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Resting Metabolic Rate (Harris-Benedict) Calculator

Estimate your resting calorie burn

How it is calculated

The tool applies the revised 1984 Harris-Benedict equations, with weight in kg, height in cm and age in years. For men: RMR = 88.362 + 13.397 × weight + 4.799 × height − 5.677 × age. For women: RMR = 447.593 + 9.247 × weight + 3.098 × height − 4.330 × age. The answer is in kilocalories per day, rounded to a whole number.

Weight and height must be above zero. Any sex value other than female uses the male formula. A negative total is shown as 0. The equation is an average estimate for adults; it ignores muscle mass, so people who are very muscular or have a lot of body fat can differ noticeably. The figure is resting energy only, not total daily needs with activity.

Worked example

A 30-year-old woman, 65 kg, 165 cm. Start with 447.593. Add 9.247 × 65 = 601.055 to get 1,048.648. Add 3.098 × 165 = 511.170 to get 1,559.818. Subtract 4.330 × 30 = 129.9 to get 1,429.918, which rounds to 1,430 kcal per day.

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Common mistakes

  • Entering weight in pounds or height in inches. The formula expects kg and cm, so those inputs give wrong results.
  • Treating the result as daily calorie needs. It is resting energy only; activity must be added on top.
  • Choosing the wrong sex option, which shifts the estimate by about 100 to 200 kcal in typical cases.
  • Expecting precision. The equation is an estimate and can be off by a few hundred kcal for an individual.

About this calculator

This calculator uses the revised (1984) Harris-Benedict equation to estimate resting metabolic rate — the calories your body burns at rest just to keep organs, breathing and circulation running. For men: RMR = 13.397 × weight(kg) + 4.799 × height(cm) − 5.677 × age + 88.362. For women: RMR = 9.247 × weight(kg) + 3.098 × height(cm) − 4.330 × age + 447.593. The 1984 revision recalibrated the original 1919 formula against a larger, more modern dataset.

It's one of the two equations (alongside the newer Mifflin-St Jeor) that dietitians and calorie-tracking apps use as the starting point for a daily calorie target: multiply RMR by an activity multiplier to get total daily energy expenditure, then set a deficit or surplus from there for weight loss or weight gain goals.

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