Fitbit and TDEE?

Francl27

Most of my exercise is walks so I've been pretty much basing my activity level on what my fitbit tells me, but I'm a bit stumped.

Yesterday, for example, I walked 6.5 miles total, had 15,000 steps, and it says my calorie burn was less than 1900... How is that even possible? I'm 35, 5'5", 9 lbs overweight (20 from goal), at 159 lbs. I seem to burn more calories when I have 'very active minutes' (I had 9), but it just seems kinda random too... I mean just walking on the treadmill at 3.6 mph gives me very active minutes.

When I enter my info in Scooby, that's less than the TDEE for lightly active (sedentary is 1770, lightly active 2030)... but I walk at least 5 miles every day, I don't exactly consider myself even moderately active (I do some strenght/cardio work outs that I add) but lightly active seems a stretch.

What's your experience with that? It's quite a bummer, and I'm scared of what my fitbit will tell me when I'm 20 lbs lighter!