Inaccurate distance with Charge 2

[dbmarcos]

I have been using my HR2 for years road running. After recently moving to Brazil and due to Covid restrictions I am forced to run in a small park (520 meter track). I run between 20 and 30 laps but my fitbit only ever indicates 8kms to 12kms....I have measured and adjusted my stride with little to no effect. Today's run showed 15000 steps but only 11.93kms. Further more I have started using MyMapRun that confirms my calculations and correct distances.  Please advise how I can correct this error?

Moderator edit: updated subject for clarity

[AlvaroFitbit]

@dbmarcos I hope you're doing well!

Let me help you with your distance calculation with your Charge 2 and thank you for troubleshooting this issue. How did you calculated your stride length. As you know 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. You could also try using the default stride length by using a 0 instead of a measurement there.

Let me know how it goes.

[dbmarcos]

Good Afternoon

Thanks for your reply and advice.

I did use the instructions to adjust my stride manually however this did to
make hate readings more accurate. My last today indicated 8.39kms that was
9666 steps, using MyMaps I confirmed my actual distance is more correct
10.25kms, this I have confirmed many times with laps run as the track is
520m long.

I calculated my stride as 79 steps per 100 meters = 126cm and if I then
take my last run of 9666 steps my distance should be closer to 12.2kms not
8.39kms

Your advice will be appreciated
Marcos