How is it possible to burn 874 calories with only 714 step taken?

[zsuzsa]

Is it possible that my fitbit is not accurate? I'm baffled.

[Kcpiper]

Yes, but most of those calories burned do not come from the steps. Most of those are from your BMR (Basal Metabolic Rate).  The BMR is what you burn just to stay alive.

[tally_]

Did you find this in the morning? The fitbit will reset at midnight for the next day. You are burning calories even when  you're sleeping! When I wake up in the morning I have burned almost 600 calories. This is simply the energy it takes to keep my body alive. (aka BMR)

You can easily burn thousands of calories just laying in your bed, given enough time. This, however, is definitely not recommended. 

[Odyssey13]

Welcome to the forums @zsuzsa

@Kcpiper  and @tally_  are right.

This article on burned calories may help you. click to read