Your Total Daily Energy Expenditure (TDEE) is the total calories your body burns in a day — combining your resting metabolic rate, the thermic effect of food, and all physical activity. Knowing your TDEE lets you set meaningful calorie targets: eat below it to lose weight, match it to maintain, or exceed it to gain.
This calculator uses the Mifflin-St Jeor equation for BMR — the most validated formula for adults — then multiplies by a PAL (Physical Activity Level) factor: Sedentary × 1.2, Light activity × 1.375, Moderate × 1.55, Active × 1.725, Very active × 1.9. The result is your estimated daily calorie burn. Note: this is a population average — individual variation can be ±200–400 kcal.
A deficit of 500 kcal/day theoretically produces ~0.5 kg/week of fat loss (since 1 kg of fat ≈ 7,700 kcal). Sustainable deficits are 300–750 kcal below TDEE. Very large deficits often cause muscle loss and metabolic adaptation.
Calories in vs out is the correct framework, but the equation isn't fixed. Metabolic adaptation (the body reducing TDEE in response to deficit), changes in water retention, and inaccurate logging all cause deviations from the predicted rate.
Your body expends energy digesting food — roughly 20–30% of calories for protein, 5–10% for carbohydrates, and 0–3% for fat. This is already baked into TDEE estimates via the activity multiplier rather than calculated separately.
Recalculate whenever your weight changes by 3–5 kg or your activity level changes significantly. As you lose weight, your TDEE decreases and your calorie targets need to be adjusted.
See also the BMR Calculator, BMI Calculator, and the Body Fat Calculator.
⚠ Disclaimer: This calculator is for informational and educational purposes only. Results are estimates and should not be relied upon as financial, medical, or professional advice. Always consult a qualified professional before making financial or health decisions.