What is TDEE?
Total Daily Energy Expenditure (TDEE) is an estimation of how many calories you burn per day when exercise is taken into account. It is calculated by first figuring out your Basal Metabolic Rate (BMR), then multiplying that value by an activity multiplier.
How to Use This for Weight Loss
To lose weight, you need to be in a calorie deficit (burning more than you eat). A safe rate of weight loss is generally considered to be 0.5kg to 1kg per week. Drastic deficits can lead to muscle loss and metabolic slowdown.
The Mifflin-St Jeor Equation
This calculator uses the Mifflin-St Jeor equation, widely regarded as one of the most accurate BMR formulas for the general population:
Women: BMR = 10W + 6.25H − 5A − 161
Where W is weight in kg, H is height in cm, and A is age in years. Your BMR is then multiplied by an activity factor — 1.2 (sedentary), 1.375 (lightly active), 1.55 (moderately active), or 1.725 (very active) — to produce your TDEE.
A Worked Example
A 30-year-old man weighing 80 kg at 180 cm, moderately active: BMR = (10 × 80) + (6.25 × 180) − (5 × 30) + 5 = 1,780 calories. His TDEE is 1,780 × 1.55 ≈ 2,759 calories/day to maintain weight. For steady loss, he'd target roughly 2,259 — a 500-calorie deficit.
Why "Eyeballing It" Fails
Most people significantly overestimate how many calories they burn through exercise and underestimate how many they eat — a well-documented bias. Remember the rule of thumb: 1 lb of fat is roughly 3,500 calories, so a daily 500-calorie deficit yields about 1 lb of loss per week. Recalculate your TDEE every 10–15 lbs, since a lighter body burns fewer calories.