Harris-Benedict Calculator

BMR stands for Basal Metabolic Rate. It is the number of calories your body needs to perform its most basic life-sustaining functions — such as breathing, circulation, and cell production — while at complete rest for 24 hours. Think of it as the minimum energy your body needs just to stay alive.

The Harris-Benedict equation is a formula used to estimate BMR based on sex, age, weight, and height. For men: BMR = 66.5 + (13.75 × weight in kg) + (5.003 × height in cm) − (6.75 × age). For women: BMR = 655.1 + (9.563 × weight in kg) + (1.850 × height in cm) − (4.676 × age). It was originally published in 1918 and revised in 1984.

To calculate your BMR using the Harris-Benedict equation, you need four values: your sex, age (in years), weight (in kg or lbs), and height (in cm or feet/inches). Enter them into the calculator above and your BMR is computed automatically. From there, multiplying by an activity factor gives your Total Daily Energy Expenditure (TDEE).

There is no single 'good' BMR because it varies widely based on body size, age, and sex. As a rough guide, the average BMR for adult men is around 1,600–1,800 kcal/day and for adult women around 1,400–1,600 kcal/day. A higher BMR generally means your body burns more calories at rest, which is typically associated with greater muscle mass.

Once you have your BMR, multiply it by an activity multiplier: 1.2 for sedentary, 1.375 for lightly active (1–3 days/week), 1.55 for moderately active (4–5 days/week), 1.725 for very active (6–7 days/week), and 1.9 for extra active (physical job or twice-daily training). The result is your TDEE — the calories needed to maintain your current weight.

The revised Harris-Benedict equation (1984) is considered reasonably accurate for most healthy adults, but it has limitations. It does not account for body composition — muscular individuals may burn more calories than predicted, while those with higher body fat may burn fewer. For clinical or professional purposes, methods like indirect calorimetry provide more precise results.

BMR is the calories your body burns at complete rest — it excludes any physical activity. TDEE (Total Daily Energy Expenditure) accounts for your actual activity level and represents the total calories you burn in a day. To maintain your weight, you should consume approximately the same number of calories as your TDEE.

Yes. BMR generally decreases with age, partly because of hormonal changes and a natural reduction in muscle mass (sarcopenia). This is why many people find it harder to maintain their weight as they get older. Regular resistance training can help preserve muscle mass and slow the decline in BMR.