Harris-Benedict Calculator
Compare the original and revised Harris-Benedict equations and estimate your daily maintenance calories.
How to use the Harris-Benedict Calculator
- Choose the sex.
- Enter the age.
- Choose the units.
- Enter the height – feet.
- Enter the height – inches.
- Enter the height.
- Enter the weight.
- Enter the weight.
- Choose the activity level.
- Press Calculate. The result updates automatically as you type.
About the Harris-Benedict Calculator
The Harris-Benedict equation was one of the first formulas for predicting basal metabolic rate, published by James Harris and Francis Benedict in 1919 from measurements of a few hundred volunteers. Roza and Shizgal refit it in 1984 using a larger data set, and that revised version is what most calculators mean by "Harris-Benedict" today.
The two versions usually agree within a few dozen calories. Both tend to overestimate needs slightly for modern, less active populations compared with Mifflin-St Jeor, so treat the result as a starting point and adjust after a few weeks of tracking your weight.
Results are estimates for general information only and are not medical advice. Talk to a doctor or registered dietitian before making major changes.
Formula
W = weight in kg, H = height in cm, A = age in years.
Original (1919)
Men: 66.473 + 13.7516W + 5.0033H − 6.755A
Women: 655.0955 + 9.5634W + 1.8496H − 4.6756A
Revised (Roza & Shizgal, 1984)
Men: 88.362 + 13.397W + 4.799H − 5.677A
Women: 447.593 + 9.247W + 3.098H − 4.330A
Daily calories = BMR × activity factor (1.2 sedentary up to 1.9 extra active).
Example calculation
Using the default values:
- Sex = Male
- Age = 35 years
- Units = US (ft, in, lb)
- Height – feet = 5 ft
- Height – inches = 10 in
- Weight = 170 lb
- Activity level = Moderately active (exercise 3–5 days/week)
the calculator returns:
- Maintenance calories (revised): 2,753 kcal/day
- BMR – revised 1984: 1,776 kcal/day
- BMR – original 1919: 1,780 kcal/day
- Maintenance calories (original): 2,759 kcal/day
Frequently asked questions
Is Harris-Benedict accurate?
It is usually within about 10% of measured BMR for healthy adults, but it can be further off for people with obesity or very high muscle mass.
Which activity factor should I pick?
Be conservative. Most office workers who exercise three to four times a week fit "lightly" or "moderately active". Overestimating activity is the most common reason calorie targets fail.
Harris-Benedict or Mifflin-St Jeor?
Studies comparing predicted and measured metabolic rate generally favor Mifflin-St Jeor, so many dietitians use it as the default. Harris-Benedict remains common in clinical and older references.
Last updated: · Category: Health & Fitness calculators