Harris-Benedict Calculator
Published in 1918, the Harris-Benedict equation was the standard way to estimate metabolism for most of the 20th century, and is still used in many hospitals. This calculator shows the original and its 1984 revision together.
Original equation
kcal/day
Enter your age, height and weight
Harris & Benedict (1918)
Revised equation
kcal/day
± kcal (95% confidence range in the paper)
Roza & Shizgal (1984)
Two versions of the same equation, shown separately.
Most dietitians now start from Mifflin-St Jeor, which tested as more accurate in a 2005 evidence review.
Your results are attached to the form below
These figures are estimates for general awareness only and are not medical advice or a diagnosis. Read our Medical Disclaimer.
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How this is calculated
Original (Harris & Benedict, Proceedings of the National Academy of Sciences, 1918): men 66.4730 + 13.7516 × weight + 5.0033 × height − 6.7550 × age; women 655.0955 + 9.5634 × weight + 1.8496 × height − 4.6756 × age. Revised (Roza & Shizgal, American Journal of Clinical Nutrition, 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. Weight in kg, height in cm, age in years.
Original or revised?
In 1984 Roza and Shizgal re-ran the analysis with the original subjects plus data Benedict published later, giving the revised equations. They found the equations predict resting energy expenditure within about ±14% for well-nourished people, but are unreliable for people who are malnourished.
Harris-Benedict today
A 2005 evidence review found the newer Mifflin-St Jeor equation more accurate for most people, so dietitians now usually start there. Harris-Benedict remains useful for comparison and is still found in many clinical references.
Related calculators
Compare it with other equations in the TDEE Calculator, or see the RMR and BEE calculators.
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