TDEE Calculator

Total Daily Energy Expenditure (TDEE) is the total number of calories your body burns in a 24-hour period. It encompasses all energy expenditure: the calories burned to maintain basic life functions at rest (Basal Metabolic Rate or BMR), the energy used to digest food (Thermic Effect of Food, approximately 10% of intake), non-exercise activity thermogenesis (NEAT -- fidgeting, walking, standing), and deliberate exercise (Exercise Activity Thermogenesis or EAT).

This calculator uses the Mifflin-St Jeor equation, which is considered the most accurate BMR prediction formula for most adults. Published in 1990, it was validated against indirect calorimetry and shown to predict BMR within 10% for the majority of individuals. The formula is: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age) + 5 for males, and the same formula minus 161 instead of plus 5 for females. TDEE is then calculated by multiplying BMR by an activity factor ranging from 1.2 (sedentary) to 1.9 (extra active).

Understanding your TDEE is the foundation of any nutrition plan. To lose weight, eat below your TDEE (calorie deficit). To gain weight, eat above your TDEE (calorie surplus). To maintain weight, eat at your TDEE. The Mifflin-St Jeor equation replaced the older Harris-Benedict equation (1918) as the recommended formula after the American Dietetic Association review found it to be the most reliable predictor of energy needs in non-obese and obese individuals.

Follow these steps to calculate your TDEE:

1. Select your unit system -- choose Metric (kg/cm) or Imperial (lb/ft) for weight and height inputs.
2. Choose your gender -- the Mifflin-St Jeor equation uses different constants for males and females to account for differences in body composition and hormonal metabolism.
3. Enter your age -- metabolic rate decreases with age, approximately 1-2% per decade after age 20, primarily due to loss of lean muscle mass.
4. Enter your weight and height -- use your current weight, measured in the morning before eating for the most consistent reading.
5. Select your activity level -- be honest with this selection, as it has the largest impact on TDEE. Sedentary (desk job, little exercise), Lightly Active (light exercise 1-3 days), Moderately Active (moderate exercise 3-5 days), Very Active (hard exercise 6-7 days), or Extra Active (very intense exercise plus physical job).

The calculator will display your BMR, TDEE with activity multiplier, and recommended calorie targets for weight loss (-500 cal), mild weight loss (-250 cal), maintenance, mild weight gain (+250 cal), and weight gain (+500 cal).

Accurately estimating your TDEE is the single most important step in any nutrition plan. Without knowing how many calories you burn, it is impossible to determine the appropriate intake for your goals. Many people underestimate their calorie consumption by 30-50% and overestimate their calorie expenditure, leading to frustration with weight management. TDEE provides an objective starting point for calculating a proper calorie target.

For weight loss, a deficit of 500 calories below TDEE produces approximately 1 pound of fat loss per week (3,500 calories per pound). For muscle gain, a surplus of 250-500 calories above TDEE, combined with progressive resistance training and adequate protein, supports lean mass gains while minimizing fat accumulation. Athletes and highly active individuals may have TDEEs exceeding 3,000-4,000 calories and need to plan meals carefully to meet their energy demands.

Your TDEE is not a fixed number -- it fluctuates daily based on activity, and it changes over time as your weight, age, and body composition change. As you lose weight, your TDEE decreases (smaller body requires less energy), so you may need to recalculate every 10-15 pounds of weight change. The most accurate way to determine your actual TDEE is to track calorie intake and weight changes over 2-4 weeks, then adjust the calculated estimate based on real-world results. Consult a registered dietitian for personalized nutrition planning.