Distance discrepancies

[michelle_2187]

I've been on several runs now where I track my run using GPS yet I get two different distances as to how far I've run. For example, my run this morning when I look at the map says 12.7km but when I look at the graphs that compares previous runs its saying 14km???

[murjd17]

Could you give a little bit of clarification on the issue? Are you saying that two runs on the same route gave you two distances or are you saying that your Fitbit told you one distance when you finished the run but when you open the app it gave you a different distance? It would also be helpful to know if you're running with your Fitbit connected to GPS on your phone or if this is a Fitbit that has built in GPS.

[michelle_2187]

• For  clarification it was the same run. See images below the first is the map and says 12.7km the second is comparing to previous runs, the last bar being the run the map shows but the distance there says 14.35km.

• My fitbit is the alto so It uses to GPS off my phone which I had with me and was turned on for the duration of the run.

  

[murjd17]

Thank-you for the clarification and it's very helpful. The short answer is that it's likely your phone's fault.

The longer answer: I have found that my GPS tracked distances over the past few years can vary by up to 20% based on variables such as weather/cloud cover, season (do the trees have leaves on them?), and sometimes time of day. The ways to address this depend on the phone you have but I'm assuming you have an Android based on the forum you've posted in. Here are some steps I've learned to generally get the variability down to about 5% or less:

1. Training runs with less overhead cover (think tall buildings and trees) will generally give you a better GPS signal

2. Try switching the GPS mode to high accuracy - search for a tutorial on how to do this with your phone.

3. Calibrate the compass on your phone before starting a run

4. Sync your fitbit with the app just before starting the run

*I also upgraded my phone about a year ago and noted a marked improvement in accuracy with the newer phone.

One other aside - I've found that the combination of my phone and fitbit seems to be more accurate if I initiate the run from the fitbit rather than the app. There is an app called GPS status that you can use to check the margin of error for your phone's GPS at a given time if you're curious