Inspire not accurately tracking distance consistently

[AuntieTaco]

My fitbit was working fine for the first month, it would accurately track my walk routine, then about 2 weeks ago, I had a day where it didn't accurately track my walk.  I have a mapped out route that I take so I know how far I should have walked (give or take a few feet).  I had walked over 2 miles before my Inspire registered the first mile. By the end of my walk, which is normally 5 miles, the Inspire had only logged 1.47 miles.  When I got home I connected it to the charger and restarted it, that seemed to fix the problem and it was back to normal the following day. Last week, it did the same thing.  Again I restarted when I got home and it seemed ok.  This week, it's done the same thing Monday, Tuesday and again today (Wednesday).  It's not fully tracking my miles, but it seems to track the steps, which is odd.  For example, a day where I walk 36,000 steps is tracking LESS miles than a day when I walk say 15,000 steps.  

The Inspire is properly connected to my iPhone, it doesn't have a charge less than 75% and when I searched, I made sure all my settings were correct (i.e. location is on, Bluetooth, etc).

The only thing I can think of, and I searched but couldn't find anything on this, is that some days I take my 2nd phone with me because I'll hook it to the hotspot on main phone and play Pokemon go.  I was playing Pokemon Go using my hotspot yesterday and today.  I did take a 2nd walk on my lunch break without the 2nd phone and no hotspot on and it did seem to track my mileage better. This could be just an odd coincidence, I don't know, but at this point I'm at my wits end.  I need something to reliably track my distance as my walks are for physical therapy. I welcome any thoughts and suggestions because my next step is to chuck the fitbit in the trash as I'm so frustrated.

Moderator edit: updated subject for clarity

[AlvaroFitbit]

@AuntieTaco I hope you're doing well! Sorry for the delay in my reply.

Let me help you with your Inspire not detecting your distance correctly. Are you using the option on your Fitbit app to tracker a walk/run or just the tracker? 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.

[AuntieTaco]

Hi, thanks for the message.  I'm using the option in the fitbit app to track the workout.  I know how to set it up and use it as it does on occasion accurately track my steps. Normally I wouldn't have an issue with "user error", but in this case I don't believe it is a user error as it is not always a problem.  I use this system on a daily basis and it works some days and not others, so if it was a user error then the result would be consistent.

On the days it is not working correctly, it's logging the steps but not the distance. For example (and I'm making up the numbers as I do not have my phone with me to get the actual figures), on day A I will walk 20,000 steps and it will log 10 miles, the next day, I will do the exact same walk, the exact same route and the exact same amount of time and it will log say 20,100 steps but only 5.5 miles, the 3rd day, it'll track 19,780 steps and log 12 miles.  It's all over the place.  Then I'll go a week or two and it will be fine, then it starts this issue all over again.

While I understand that the same route is never walked exactly the same way, I'm willing to accept a margin of .5 miles give or take whether I walk around a car, cut corners, etc. but the same route with a discrepancy as described above is maddening. Also, I wear an apple watch as well and that is relatively consistent in the tracking of the distance give or take 1/2 a mile.

At first I thought it could be an issue with the fact that I use my hotspot sometimes when I walk, but this morning everything seemed fine with the tracking of my walk and this time I used my hotspot, so maybe that's not it.