Calorie burn inaccurate?

[jjonesj]

The calories burned on my flex 2 seem to be inaccurate. Fitbit is saying that i burn 1,500 calories a day without exercising, however using an online calculator my BMR is almost at 1,600 and my maintenance calories are almost 2,100. How is this possible? Which one should I listen to? I eat around 1,400 a day and am exercising with an apparent calorie burn of 400-500 a day. According to fitbit this would be around a 500/600 deficit, but according to my online TDEE this would be a deficit over 1,000. Which is correct?

[JohnnyRow]

Check that your weight and height are entered correctly, at least approximately.

[jjonesj]

Weirdly, my details on my Fitbit are the exact same details I’ve been using on these online calculators, so I really have no idea why they are so different

Thanks anyway!

[JohnnyRow]

Look at you calories burned chart overnight while you are asleep.  It show calories burned per 15 minute interval.  From that you can get what Fitbit is using for you BMR.  In every case I have seen, this comes out very close to an on-line BMR calculator.

If you say fitbit says you are burning 1500 calories total per day, but a BMR calculator says your BMR is 1600 calories, I would be interested to know your age, sex, height, weight if you don't mind sharing, to check you numbers, and also what Fitbit shows for calorie burn when asleep..  Something definitely seems off here.