Question 1

How do I convert a FIT file to GPX?

Accepted Answer

Open it here and press .gpx. The GPX has every GPS point with its time and elevation, plus heart rate, cadence, temperature and power where the device recorded them, so uploading it elsewhere keeps the data rather than just the line on the map. An indoor activity has no positions, so it has no GPX - the CSV still has everything.

Question 2

Why are some numbers missing?

Accepted Answer

Because the device did not record them. A run without a chest strap or wrist sensor has no heart rate, and most running watches record no power. The page shows a chart only for a channel that is actually in the file.

Question 3

Which FIT files will it not open?

Accepted Answer

Files that are not activities - device settings, daily step monitoring and workout plans are FIT files too - and a file cut off partway through, which happens when a watch loses power or a transfer stops. Both are named as such rather than shown as an empty page.

Question 4

Is my activity uploaded anywhere?

Accepted Answer

No. The file is decoded in this page by fit-file-parser. That matters with a FIT file more than most, because its GPS track starts and ends at your front door.

Free FIT file viewer