TDEE Calculator

The TDEE Calculator computes your Total Daily Energy Expenditure — the total number of calories you burn in a day across all activities, from resting metabolism to exercise and food digestion. TDEE is the single most important number in personalized nutrition planning: it is your maintenance calorie level, the precise caloric intake at which your weight neither increases nor decreases.

TDEE is calculated by multiplying your Basal Metabolic Rate (BMR) — the energy needed to sustain life at rest — by an activity multiplier that accounts for your daily movement and exercise habits. This two-step calculation was formalized in nutritional science through the work of Harris and Benedict (1919) and later refined by activity factor systems popularized by exercise physiologists.

The activity multipliers used in TDEE calculation are critical to accuracy. The sedentary multiplier (1.2) applies to office workers with little movement beyond walking to and from a car. The lightly active multiplier (1.375) covers individuals who exercise 1–3 days per week but otherwise have low activity. The moderately active multiplier (1.55) — the most commonly applicable category — covers those exercising 3–5 days per week with moderate intensity. The very active (1.725) and extra active (1.9) multipliers apply to competitive athletes, construction workers, and those with physically demanding lifestyles.

Understanding your TDEE enables a range of nutritional strategies. For weight maintenance, eating at your TDEE keeps body weight stable. For weight loss, a deficit of 300–550 kcal below TDEE produces safe fat loss. For muscle building, a surplus of 200–500 kcal above TDEE provides the energy and anabolic environment needed for hypertrophy. The flexibility of this framework is what makes TDEE-based nutrition planning so widely applicable.

TDEE is not static. It changes with body composition, age, activity level, metabolic adaptation to dieting, seasonal temperature changes, and health status. Recalculating your TDEE monthly during weight changes is recommended, particularly during active weight loss or gain phases, as your calorie needs shift with your body weight.

The most accurate way to measure TDEE is through laboratory indirect calorimetry (measuring oxygen consumption and CO2 production). For practical daily use, the Mifflin-St Jeor equation used here provides estimates within 10% of measured values for most adults — accurate enough to serve as a reliable starting point that can be refined through 4–6 weeks of real-world calorie tracking and weight monitoring.