What is BMR?
Your basal metabolic rate (BMR) is the energy your body burns at rest just to keep running — breathing, circulation, keeping warm. Factor in daily movement and exercise and you get your total daily energy expenditure (TDEE): roughly the calories you need to maintain your current weight.
This calculator estimates BMR with the widely used Mifflin-St Jeor equation:
- Men: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
- Women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
- TDEE = BMR × activity factor
You can enter metric (kg/cm) or imperial (lb, ft and in) values; imperial inputs are converted with 1 lb = 0.45359237 kg and 1 in = 2.54 cm.
Choosing an activity factor
| Activity level | Factor | Typical example |
|---|---|---|
| Sedentary | 1.2 | Desk job, little or no exercise |
| Lightly active | 1.375 | Exercise 1–3 days a week |
| Moderately active | 1.55 | Exercise 3–5 days a week |
| Very active | 1.725 | Exercise 6–7 days a week |
| Extra active | 1.9 | Physical job or training twice a day |
The results table lists TDEE for every level, so you can compare and pick the one closest to your routine.
Calorie targets for losing or gaining
A common approach to weight loss is eating about 500 kcal a day below maintenance, which works out to roughly 0.45 kg (1 lb) per week. To gain weight, add 300–500 kcal a day. Real-world results vary with your body and activity.
Limitations
The equation is an estimate, and body composition such as muscle mass can make your real value differ. If you have a medical condition or are pregnant, ask a professional. To check whether your weight is in a healthy range for your height, use the BMI calculator. Everything is calculated in your browser.