Charge 2 is consistently overestimating my running distance

[merholo]

I was clued into this recently when I ran a standardised race with my fitbit on. Set distance was 6km, fitbit said 6.7km. I've started testing it by using the fitbit app to track while running as well as the band. GPS map will return exactly the same, yet fitbit is always ~half a km or more longer than fitbit app.

I have stride set to automatic, but the number in there doesn't even match either of the distance when I multiply by distance, so not sure if that's the issue. This is really frustrating and should not be happening, it makes all the information completely useless as it's not accurate, and the app itself doesn't have any heart rate data so I lose data if I use that method. If the app itself can get it right, there's not reason fitbit itself shouldn't, they're linked!!!

Edit: a thought, could it be the swinging of my arm that accumulates? I didn't think fitbit would be this sensitive/precise?

I'm considering upgrading soon so I'd like a solution or credible explanation before I even consider another fitbit product.

Moderator edit: updated subject for clarity

[AlvaroFitbit]

@merholo Welcome! It's great to see you around! Sorry for the delay in my reply.

Let me help you with your distance calculation. Your device uses the number of steps and stride length to calculate the distance. You can improve the accuracy by measuring and logging your stride length. Feel free to use these instructions to do this.

Let me know how it goes.

[merholo]

I just don't think this is the correct solution. Stride length is set to automatically adjust based on GPS. If the app tracking can get the GPS distance right, then my Charge 2 should also be able to get it right and then adjust stride length based on that.