The definition
TDEE — Total Daily Energy Expenditure — is the total number of calories your body burns in a day. Eat that many calories and your weight stays stable. Eat fewer and you lose; eat more and you gain. Everything else is detail.
The four parts of your daily burn
- BMR (60–70%) — your Basal Metabolic Rate: calories burned at complete rest just to stay alive.
- Activity (NEAT + exercise, 15–30%) — everything you do, from workouts to fidgeting and walking.
- Thermic effect of food (~10%) — the energy used to digest what you eat (protein costs the most).
Add them up and you get your TDEE. Our TDEE calculator estimates it using the Mifflin-St Jeor equation and your activity level.
How to use your TDEE
- Lose fat: eat about 300–500 calories below TDEE (a 10–20% deficit).
- Maintain: eat around TDEE.
- Build muscle: eat about 200–400 above TDEE, with strength training.
Why it's an estimate
TDEE formulas are starting points — your true burn varies with muscle mass, genetics, and daily movement, and it changes as your weight changes (a lighter body burns less). Use the calculated number for 2–3 weeks, watch your weight trend, and adjust. The scale is the real feedback; the formula just gets you close.
The takeaway
You don't need to obsess over a perfect number. Know your rough TDEE, pick a goal, set calories accordingly, then let real-world results fine-tune it.