Harris-Benedict BMR Calculator

An alternative BMR formula to Mifflin-St Jeor.

How the Math Works

The Harris-Benedict BMR Calculator uses the revised Harris-Benedict equation to estimate your basal metabolic rate - the calories your body burns at rest to maintain basic life functions. For men, the formula is: BMR = 88.362 + (13.397 x weight in kg) + (4.799 x height in cm) - (5.707 x age in years). For women, it's slightly different: BMR = 447.593 + (9.247 x weight in kg) + (3.098 x height in cm) - (4.336 x age in years). This equation was updated in 1990 to provide more accurate estimates than the original 1919 version by incorporating more comprehensive metabolic data.

Practical Applications

To use this calculator, simply enter your gender, age, weight in kilograms, and height in centimeters. The calculator will automatically apply the appropriate revised Harris-Benedict formula and output your estimated BMR in calories per day. This calculation serves as the foundation for determining your total daily energy expenditure when you multiply your BMR by an activity factor (ranging from 1.2 for sedentary to 2.4 for extreme athletes). You can use this BMR figure to set realistic weight loss, maintenance, or muscle gain goals by creating appropriate caloric deficits or surpluses.

Day-to-Day Use

Knowing your BMR empowers you to make informed decisions about nutrition and fitness in your daily life. If you're trying to lose weight, understanding your baseline calorie needs helps you create a sustainable deficit without starving yourself. For weight maintenance, you can balance your intake with your total daily energy expenditure. Athletes use BMR calculations to optimize performance and recovery nutrition. Even those simply wanting to improve their health can use this information to ensure they're fueling their bodies adequately for their age, gender, and body composition, leading to better energy levels and overall well-being.

Worked example

Male, 70 kg, 175 cm, 30 → ~1,696 kcal.

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