Harris-Benedict Calculator (Basal Metabolic Rate)

Written by Great Medico

Updated September 24, 2026 •2 min read

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Nutrition planning gets easier when a broad goal is translated into a concrete daily number. Harris-Benedict Calculator (Basal Metabolic Rate) does that using only the inputs and rules implemented in this tool.

What this calculator does

The Harris–Benedict approach estimates basal metabolic rate from age, sex, height, and weight. This calculator uses the revised Harris–Benedict equations, which updated the original early-20th-century coefficients. Nutrition equations are planning tools: real energy and nutrient needs still vary with physiology, goals, health conditions, and the quality of the input data.

How to use it

Enter or select Sex, Age, Height, and Weight. Use the units offered by the calculator and keep measurements consistent when you plan to compare results over time.

How the calculation works

For males and females, the calculator applies the corresponding revised Roza–Shizgal equation to age in years, height in centimeters, and weight in kilograms. The result is estimated basal energy use in kilocalories per day.

Example

For the sample values prefilled in this calculator, the primary result is 1734.3 kcal/day (Harris-Benedict BMR). This example is there to show how the inputs flow through the implemented equation; replace the sample values with your own measurements before using the result.

How to interpret the result

BMR represents the energy your body is estimated to use at rest before a separate activity adjustment. It is a useful baseline for energy planning, not a measurement of exactly how many calories you burn each day.

Limitations and notes

Prediction error is normal because metabolism varies with body composition, illness, hormones, temperature, and other factors. The equation does not directly measure lean mass, and people at body-size extremes may differ more from the predicted value. For planning, compare the estimate with real-world trends over time instead of reacting to one day. Food-label accuracy, portion estimates, hydration, and activity can all create noise, so modest adjustments are usually more informative than chasing exact calculator precision.