BMR Calculator
Calculate your Basal Metabolic Rate to know how many calories your body burns at rest
What is BMR?
Basal Metabolic Rate (BMR) is the number of calories your body needs to perform its most basic life-sustaining functions while at complete rest. These functions include breathing, blood circulation, cell production, nutrient processing, and temperature regulation. BMR typically accounts for 60-75% of your total daily calorie expenditure, making it the foundation for calculating your overall energy needs.
BMR Formulas Explained
The most commonly used BMR formulas are the Mifflin-St Jeor equation and the Harris-Benedict equation. The Mifflin-St Jeor equation (developed in 1990) is considered more accurate for modern populations: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age + 5 (men) or -161 (women). The older Harris-Benedict equation (1918) tends to overestimate calorie needs but is still widely used in clinical settings.
Factors Affecting BMR
Several factors influence your BMR beyond age, weight, height, and sex. Muscle mass significantly increases BMR since muscle tissue burns more calories than fat tissue. Hormones (especially thyroid hormones), body temperature, climate, stress levels, and genetics also play important roles. Crash dieting can lower BMR as your body adapts to conserve energy, which is why sustainable approaches to weight management are recommended.