What the Harris-Benedict equation does
The Harris-Benedict equation estimates your basal metabolic rate (BMR) — the calories your body burns at complete rest. For men: 88.36 + 13.40 × kg + 4.80 × cm − 5.68 × age; for women: 447.59 + 9.25 × kg + 3.10 × cm − 4.33 × age. A 30-year-old, 80 kg, 180 cm man gets about 1,854 calories. The modern replacement equation is used by the BMR calculator.
How to use this calculator
Enter sex (1 male, 0 female), age, weight in kg and height in cm. The result is your BMR. Multiply it by an activity factor (1.2–1.9) for your total daily calories, or use the maintenance calorie calculator.
Harris-Benedict vs. Mifflin-St Jeor
Both estimate BMR. The Mifflin-St Jeor equation (used in our RMR calculator) is generally considered slightly more accurate for modern populations, while the revised Harris-Benedict remains widely used and gives close results. Either is a solid starting estimate. To turn that total into daily food targets, use the macro calculator.
An estimate, not a measurement
Equations approximate the average person; true BMR varies with muscle mass, genetics and hormones. Use the figure as a baseline and adjust to your real-world results. For general information only, not medical advice.
Frequently asked questions
- How do I calculate BMR with the Harris-Benedict equation?
- For men: 88.36 + 13.40×weight(kg) + 4.80×height(cm) − 5.68×age. For women: 447.59 + 9.25×weight + 3.10×height − 4.33×age.
- What is BMR?
- Basal metabolic rate — the calories your body burns at complete rest to maintain basic functions. It's the largest part of daily energy use.
- Is Harris-Benedict or Mifflin-St Jeor better?
- Mifflin-St Jeor is often considered slightly more accurate today, but the revised Harris-Benedict gives close results and is widely used.
- How do I get total calories from BMR?
- Multiply BMR by an activity factor from 1.2 (sedentary) to 1.9 (very active) to estimate total daily energy expenditure.
- Does the equation account for muscle mass?
- No. Harris-Benedict uses only sex, age, weight and height, so it cannot tell muscle from fat. Two people with identical stats but different body composition get the same number, which is why lean, muscular people often burn more than predicted.