BMR Calculator (Basal Metabolic Rate)

How It Works

Your Basal Metabolic Rate (BMR) is the number of calories your body needs per day just to maintain basic life functions — breathing, circulating blood, regulating temperature, and cell production — while completely at rest. Think of it as the energy cost of simply being alive. The Mifflin-St Jeor equation (1990) is the most widely recommended by dietitians today because it tends to be more accurate than older formulas. The Harris-Benedict equation (1919, revised 1984) is also shown for comparison. BMR typically accounts for 60-75% of your total daily energy expenditure. The remaining calories come from physical activity and the thermic effect of food (digestion). Your BMR decreases with age and is higher with more lean muscle mass.