The total calories you burn per day, based on your metabolism and activity level.
Maintenance calories — to keep your current weight.
Targets are based on a ~500 kcal/day deficit/surplus.
TDEE (Total Daily Energy Expenditure) is the full number of calories you burn in a real day — not just at rest, but through walking, work and training too.
You get it by multiplying your basal metabolism by an activity factor: 1.2 for a sedentary life up to 1.9 for very hard exercise. A BMR of 1,780 with moderate activity (×1.55) gives a TDEE of about 2,760 calories.
It is the most useful figure for a nutrition goal: eat below your TDEE to lose weight, above it to gain.
Think honestly about your week: sedentary 1.2, light 1.375, moderate 1.55, hard 1.725, very hard 1.9. Most people overestimate — choose conservatively.
A deficit of about 500 calories below your TDEE is roughly half a kilo per week. Larger deficits are harder to sustain.
Yes — as your weight and activity change, your TDEE shifts, so it is worth checking every few weeks.