How do I convert a FIT file to GPX?

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.

Why are some numbers missing?

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.

Which FIT files will it not open?

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.

Is my activity uploaded anywhere?

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.

Stays on your computer Map tiles come from openstreetmap.org, which reveals the area of the activity; untick the map to avoid itHow this works

Free FIT file viewer

See a Garmin, Wahoo or Coros activity on a map with its charts and laps — entirely in your browser

Drag & drop a .fit file here, or browse

Rides, runs, swims and workouts from a watch or bike computer · Garmin .zip and Strava .fit.gz exports work too · nothing is uploaded

Show the route on a map (the map squares come from OpenStreetMap; untick to request nothing from them)

About this FIT file viewer

FIT is the file a Garmin watch or bike computer - and most Wahoo, Coros, Suunto, Polar and Hammerhead devices - writes for every ride, run and swim. This opens one without an account on the maker’s app: the route on a map, the headline numbers (distance, time, pace or speed, elevation gain, heart rate, power, cadence, calories), a chart for every channel the device recorded, and a table of laps. A multisport file shows each leg separately.

It also converts: GPX keeps the route, time, elevation, heart rate, cadence, temperature and power in the form Strava, Komoot and Garmin Connect read back, and CSV gives every sample as a spreadsheet row. The file is read in the page. Apart from the reader code, fetched once when you open a file, the only thing fetched while you look is the map tiles, from OpenStreetMap, and you can turn the map off before opening a file so they are not fetched at all. It is free to use, with no account and no upload limit, and it runs entirely in your browser: nothing is uploaded, and while the page stays open, a feature you have already used keeps working offline.

What you can do

Open a FIT activity file from Garmin, Wahoo, Coros, Suunto, Polar, Hammerhead and other devices
Open a Garmin Connect .zip export or a Strava .fit.gz file as it is
See the route on a map, with the start and finish marked, or turn the map off so no map tiles are fetched
Distance, timer and elapsed time (and moving time when the device records it), pace or speed, elevation gain, heart rate, power, cadence and calories
Charts of elevation, speed or pace, heart rate, cadence, power and temperature, for whatever the device recorded
Hover over a chart to see where that moment was on the map
A table of laps, and each leg of a multisport activity shown separately
Convert FIT to GPX, keeping heart rate, cadence, temperature and power
Export every recorded sample to CSV
Switch every number between metric and imperial units

How to open a FIT file

Copy the .fit off the device - on a Garmin it is in GARMIN/Activity when the watch is plugged in - or export it from the app. Garmin Connect’s .zip and Strava’s .fit.gz can go in as they are.
Drop it onto the page, or click to choose it.
Read the summary, follow the route on the map, and hover over a chart to see where that moment happened.
Press .gpx to convert it for another app, or .csv for a spreadsheet. Miles switches every number to imperial units.

Questions

How do I convert a FIT file to GPX?: 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.
Why are some numbers missing?: 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.
Which FIT files will it not open?: 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.
Is my activity uploaded anywhere?: 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.