Fitbit Charge 3 overestimating my step to calorie burn

[Mel0n]

I recently got a Charge 3 and it seems to be massively overestimating my calorie burn through my steps at home. I live a very sedentary life and I got this tracker to motivate me to go out for walks. But it's doing the opposite.

According to the Mifflin equation, my BMR is around 1380 calories, I'm female, 29 years old, 1.64m (5'4) and 66kg (145lbs). Fitbit seems to account for 5 calories per 5 minutes for me when I don't take any steps so it calculates a BMR of 1440.

Yesterday I did (according to fitbit) 1330 steps in my house, cooking, cleaning, going from room to room. Fitbit also says I burnt a total of 1650 calories. I assume that's including my BMR so, 1650-1440=210 calories doing 1330 steps in the house. I'd say that's about 10 4-5 times more than the actual calorie burn. My awake heart rate was between 95 and 65 with only one spike at 105.

Clearly, my actual calorie burn for the day would be closer to 1410 (accounting for my correct BMR and activity) not 1650.

I contacted support and they told me to restart the device multiple times and to walk around the house counting my steps. Obviously none of this would help with the actual problem so I feel a little disappointed.

Any advice on how to make this fitbit more accurate?

[JohnnyRow]

So you are saying 210 calories for 1330 steps is about ten times too high; that means you believe 21 calories for 1330 steps, which is roughly 6 tenths of a mile, meaning 35 calories per mile.  You are obviously doing internet research, so see if 35 calories per mile looks reasonable.

Also you assuming you are either at your BMR or walking.  That is not accurate; just standing increases your calorie burn above BMR with no steps.

Even if accepting your assumptions, "massively" seems a bit of an overstatement for 240 calories per day, but I guess that is in the beholder's eyes.

[Mel0n]

According to this calculator, I should have burnt 48 Calories not 210. And what would happen if I walked way more? What if I walked 13300 steps? Would I have lost 2100 calories instead of 480? I would hardly call that a negligible amount. And I am even choosing to ignore the BMR discrepancy of 1380 vs 1440 because that is probably what I've lost from just standing, as you place it.

And I'm not only speaking from online research, I'm speaking from experience. I've been eating at a calorie deficit for 2 years now where I have successfully lost weight at a considerably slow and measured way, so I know that the amount of activity I do on a daily basis in the house is worth very few calories, otherwise I'd have a massive calorie deficit and way more weight loss than what I actually had.

[Meldanen]

Even 100 calories would be too much for a km considering that this is simply room-to-room walking and her fitbit counts it as more than double of that