TDEE Activity Level Guide: Choose the Right One
The activity level field is the easiest place to overestimate TDEE. Choose the level that describes your average week, including your job and daily steps, not just the workouts you wish counted more.
Why activity level changes the result so much
The calculator estimates BMR first, then multiplies it. A person with a 1,600-calorie BMR would get 1,920 calories at a 1.2 sedentary multiplier and 2,480 calories at a 1.55 moderate multiplier. That gap is large enough to decide whether a diet works.
Most mistakes happen because exercise feels hard, so people select a high activity level. But a one-hour workout does not erase a mostly still day.
Pick from your ordinary week
Look at the last two normal weeks. How many days did you train? How many steps did you average? Was your job mostly sitting, standing, walking, or physical labor? The answer should come from that pattern.
If your week varies, choose the lower level and let results tell you if it was too conservative.
Examples that make the choice easier
Sedentary fits desk work, low steps, and little planned exercise. Lightly active fits a desk job with regular walks or a few easier workouts. Moderate fits several meaningful sessions plus a decent amount of daily movement. Very active usually means hard training, a physical job, or both.
Athletes, manual laborers, and people with very high step counts may need the upper levels. Most office workers do not, even if they train.
How to know you chose wrong
If you eat at the calculator's maintenance and your average weight climbs for three weeks, the activity level was probably too high or tracking was loose. If weight drops quickly at maintenance, the estimate may be too low.
The fix is simple: adjust the target based on the trend. The first activity choice is not a confession. It is a starting estimate.
Sources and method notes
TDEETools articles explain calculator outputs in plain English. They are educational and are not medical advice.