Inspire HR is under-reporting mileage

[JAM55]

I have been walking the same 2.2 mile loop for a few weeks. I've tracked it in my car, on GPS etc. It is definitely 2.2 miles. I wear the Inspire HR on my non-dominant wrist. At the halfway point (1.1 miles) it consistently displays .85 on the screen. Why is this happening? thanks

[JohnnyRow]

Totally different ways of getting mileage, depending on whether or not using connected-GPS.

[JAM55]

I don’t usually carry my iPhone when i walk. Why would it vary so much?

[JohnnyRow]

If you are not using your phone's GPS, the distance is calculated as number of steps times stride length.  I can't think of any other way it could be expected to know distance.

I expect your stride length is set too short.  Fitbit sets a default based on your physical characteristics but has no way to know exactly.

See How do I measure and adjust stride length for my Fitbit device?

From your numbers, it seems if you increase your stride length by (1.1 / .85), it should be close.

[JAM55]

Many thanks