What is TDEE?
TDEE (Total Daily Energy Expenditure) is the total number of calories your body burns in 24 hours. It's made up of four parts: your resting metabolism (the biggest chunk), the energy used to digest food, your intentional exercise, and the fidgeting and movement you do without thinking about it.
Eat at your TDEE and your weight stays put. Eat below it and you lose; above it and you gain. That's the entire foundation of body-weight change.
The formula we use
This calculator uses the Mifflin-St Jeor equation, the most accurate BMR formula validated for the general population:
Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
TDEE = BMR × activity factor (1.2 – 1.9)
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
TDEE = BMR × activity factor (1.2 – 1.9)
We then apply a calorie offset for your goal: about 500 fewer calories a day for ~0.5 kg (1 lb) of weekly fat loss, or a modest surplus for lean muscle gain.
How to use your number
- Cutting? Aim for the −500 line, prioritise protein (~1.6–2.2 g/kg), and lift to keep muscle.
- Maintaining? Eat around your TDEE and track weekly — adjust if the scale drifts.
- Bulking? A slow +250/day surplus builds muscle with minimal fat gain.
TDEE is an estimate, not a law. Track your weight for 2–3 weeks and adjust: if it's not moving the way you want, nudge calories by ±150 and reassess.