Free Calorie Calculator – Find Your Daily Calorie Needs with the Mifflin-St Jeor Equation
Understanding how many calories your body needs each day is the foundation of any effective nutrition plan, whether your goal is weight loss, muscle gain, or simply maintaining a healthy weight. Our free calorie calculator uses the Mifflin-St Jeor equation, which research has shown to be the most accurate formula for estimating Basal Metabolic Rate (BMR) in most adults.
Your BMR represents the number of calories your body burns at complete rest — just to keep vital functions like breathing, circulation, and cell production running. The Mifflin-St Jeor equation factors in your weight, height, age, and gender: for men it is (10 x weight) + (6.25 x height) - (5 x age) + 5, and for women the same formula minus 161 instead of plus 5.
Once we have your BMR, we multiply it by an activity factor that ranges from 1.2 (sedentary) to 1.9 (very active) to calculate your Total Daily Energy Expenditure (TDEE). This is the number of calories you need to maintain your current weight. To lose weight, aim for 500 calories below your TDEE; to gain, add 500 calories.
Keep in mind that calorie calculators provide estimates, not exact figures. Individual metabolism varies based on genetics, body composition, hormones, sleep quality, and stress levels. Use these numbers as a starting point and adjust based on your actual results over 2-4 weeks. For a complete health assessment, explore also our BMI Calculator, Body Fat Calculator, and Water Intake Calculator.