Basal Metabolic Rate Calculator
Enter your details below. The calculator calculates your basal metabolic rate using the Harris-Benedict formula and shows daily calorie needs at three different activity levels.
Basal Metabolic Rate (BMR)
Sedentary, no exercise
Moderate exercise
Heavy exercise
What is Basal Metabolic Rate?
Basal Metabolic Rate (BMR, Basal Metabolic Rate) means the number of calories your body consumes per day at complete rest. This energy is used for vital functions: breathing, circulation, cell renewal, and maintaining body temperature.
BMR typically covers 60–75% of daily total energy expenditure. The rest is divided into physical activity (15–30%) and the thermic effect of food, i.e., thermogenesis (about 10%).
Harris-Benedict Formula
The calculator uses the Harris-Benedict formula, which is one of the most famous and used BMR formulas. It was originally published in 1919 and updated in 1984.
For men: BMR = 88.362 + (13.397 × weight kg) + (4.799 × height cm) − (5.677 × age)
For women: BMR = 447.593 + (9.247 × weight kg) + (3.098 × height cm) − (4.330 × age)
Activity Factors
An estimate of daily calorie needs is obtained from BMR by multiplying it by the activity factor:
| Activity Level | Factor | Description |
|---|---|---|
| Sedentary work | 1.2 | Office work, no exercise |
| Light exercise | 1.375 | Exercise 1–3 times a week |
| Moderate exercise | 1.55 | Exercise 3–5 times a week |
| Heavy exercise | 1.725 | Exercise 6–7 times a week |
| Very heavy | 1.9 | Physical work or training 2×/day |
What affects BMR?
Several factors affect BMR:
- Muscle mass – the more muscle, the higher BMR
- Age – metabolism slows by about 1–2% per decade
- Gender – men have on average higher BMR due to greater muscle mass
- Genetics – hereditary factors can cause up to 200 kcal difference
- Thyroid function – thyroid hormones regulate metabolism rate
Difference between BMR and TDEE
BMR measures resting expenditure, while TDEE (Total Daily Energy Expenditure) is total expenditure that takes into account all physical activity. If you want an accurate estimate of your daily calorie needs, use the daily calorie needs calculator, where you can select your activity level.
Sources
- Harris, J.A. & Benedict, F.G. (1918). A Biometric Study of Human Basal Metabolism. Proceedings of the National Academy of Sciences.
- Roza, A.M. & Shizgal, H.M. (1984). The Harris Benedict equation reevaluated. The American Journal of Clinical Nutrition.
