GPS distance do not match with Mapmywalk

[KBergmann]

According to MapMyWalk app (and previous GPS trackers) my usual walking trails reflect one distance, but the fitbit app will reflect a different distance, usually less than what it's supposed to be. So instead of 3 miles, the fitbit will only show 2.87 miles. How do I get the two apps to marry? 

Moderator Edit: Updated Subject For Clarity.

[RobertoME]

Hello @KBergmann, good to see you are visiting the Fitbit Community! I was reading your distance is not the same in your Fitbit account in comparison with MapMyWalk.

I'm wondering if you are tracking the exercise only with your Fitbit, syncing with MapMyWalk the wrong distance or you are tracking in both apps the same exercise?

Note that if we compare the distance in both apps, it will never be the same, due to its own functionalities it may report the distance differently. 

In this case, your Fitbit tracker will consider also your stride length configuration along with the distance reported by your GPS. This in order to cover your distance based on your step count, in case the connectivity with the GPS dropped.

If this is not the case and the GPS is not reporting the same distance, perhaps the following article will give you some additional information: Why isn't GPS working on my Fitbit device?

See you around and let me know more details if the issue persists.