TDEE Calculator

BMR (Basal Metabolic Rate) is the calories your body burns at complete rest — just keeping the lights on. TDEE (Total Daily Energy Expenditure) is BMR multiplied by an activity factor that accounts for movement throughout the day, exercise, and the thermic effect of food. TDEE is the maintenance figure: eat that, weight stays roughly the same.

Mifflin–St Jeor, the formula most commonly recommended by registered dietitians today. It outperforms the older Harris–Benedict equation in head-to-head accuracy studies, especially for the modern population. The formulas are: men → 10·kg + 6.25·cm − 5·age + 5; women → 10·kg + 6.25·cm − 5·age − 161.

They're the standard ones used across nutrition references: 1.2 sedentary, 1.375 light, 1.55 moderate, 1.725 very active, 1.9 extra active. Most people overestimate their activity level. If you sit at a desk most of the day and exercise 3 days a week, “lightly active” (1.375) is usually closer than “moderate” (1.55).

Mifflin–St Jeor predicts BMR within roughly ±10% for most healthy adults. Activity-multiplier-based TDEE has more uncertainty — easily ±15–20% — because real-world activity varies a lot. Treat the result as a starting point: pick a target, eat at that level for 2–3 weeks, then adjust based on how your weight actually changes.

The “500 kcal/day = 1 lb/week” heuristic is a useful starting point but not a guarantee. Weight loss slows as you lose mass (your TDEE drops), water and glycogen shifts can mask scale changes for weeks, and very aggressive deficits often backfire. A modest deficit (250–500 kcal) is sustainable for most people; larger ones should be supervised.