Your Basal Metabolic Rate (BMR) is the amount of energy your body needs to perform its most basic, life-sustaining functions, such as breathing, circulation, nutrient processing, and cell production, while you are in a state of complete rest. Understanding your BMR is the first step in determining your total daily calorie needs and is fundamental for setting effective weight management goals, whether for loss, gain, or maintenance. This calculator uses the widely-accepted Mifflin-St Jeor equation to estimate your BMR.