walked from just before the 38 mi marker to 39 mi marker and back fit bit recorded 4.5 mi why

[genebradford]

walked from about 1/10 mi fm 38 mi mar to 39 mi mar returned fit bit recorded 4.5mi why

[Dominique]

OK, if I understood you correctly (which is not facilitated by the complete lack of punctuation and the questionable syntax of your post), you walked back and forth between two spots separated by a distance known to be of 1 mile. You therefore expected your Fitbit to report 2 miles as the distance, but in fact it reported 4.5 miles.

Unless your Fitbit has built-in GPS (e.g. Surge, Ionic), or it can use your phone’s GPS (e.g. Charge 2), it will estimate distance as number of steps multiplied by stride length. Stride length can either be entered by you in your personal settings, or (if left empty) estimated by Fitbit based on your height. It would appear your stride length is incorrect, or your Fitbit miscounted the number of steps you took during that walk, or you misread the distance.

Anyway, your Fitbit is a fitness/activity tracker, not an odometer, so I wouldn’t pay too much attention to the distance reported.