Just got a Charge 3 yesterday, but it has logged calories for the whole period before i owned it

[Korasi]

Every single day prior to my owning my fitbit has 1747 burnt calories logged in the app. The chart is a huge block of 1747 every day going back months and months and months and I don't understand why. Surely the time before owning my fitbit should just be blank, why are these areas populated with totally arbitrary calorie burning data? I'd quite like to delete it but I don't see any obvious way of doing so. And even if there is a way I don't much fancy spending hours deleting hundreds of days one at a time...

Oh I just noticed, it says 1747 calories every day going back until december, then in december it randomly changes to 1751 every day, same thing again, it's 1751 every signle day for a couple hundred days, then it changes again to 1756 and stays like that for a few hundred days, then changes to 1761, and it keeps doing this with the number changing every few hundred days. Why is this?? I don't understand where this random data is coming from and why these regions are pupulated in the app, it makes no sense..

[JohnnyRow]

Those are your BMR (basal metabolic rate) calories that you are always burning just by being alive.  They are always credited, even when you are not wearing the tracker.

As you see, they also get credited in the past, I think as far back as you could look, not sure why.  And I don't think they can be deleted. 

I don't know why they are not all the same, but seem close enough maybe just some rounding function.

So now at least you know what Fitbit is using for your BMR daily calorie burn.

See How does my Fitbit device calculate calories burned?