FIT, TCX or GPX: which file to export, and how to get it

Three formats, three levels of detail

GPX is the oldest and simplest: an XML file with a list of points (latitude, longitude, altitude, time). Many apps add heart rate, cadence or power through extensions, but this is not guaranteed, and different apps write them differently. It is great for sharing a route; it is poor as a record of a ride.

TCX was created for fitness data. It stores laps, heart rate, cadence and, through extensions, power. It is more structured than GPX but still a text format with a fixed idea of what an activity contains.

FIT is the binary format used by Garmin and adopted by most bike computers and sensors. It is compact and, importantly, it is a stream of typed messages that can carry nearly everything the device knows. The table summarises the differences that matter to cyclists.

Information	FIT	TCX	GPX
Position, altitude, time	Yes	Yes	Yes
Heart rate, cadence	Yes	Yes	Only with extensions
Power (and left/right balance)	Yes	Power usually, balance rarely	Only with extensions
Pedalling metrics (torque effectiveness, pedal smoothness)	Yes, if the sensor sends them	No	No
Electronic shifting events (every gear change)	Yes	No	No
Device and sensor information	Yes	Little	Little
Laps and session totals	Yes	Yes	No

The practical consequence: if you ride with Shimano Di2 or SRAM AXS and want to analyse your shifting, only the FIT file keeps the gear-change events (with the number of teeth in the front and rear on many devices). Once a file is converted to TCX or GPX, those events are gone and cannot be reconstructed. Our guide on electronic shifting data explains what you can do with them.

Getting the file from your device

Whenever you can, take the file straight from the head unit, because it is the real original and nobody has touched it. Most bike computers appear as a removable drive when you plug them in with a USB cable. On a Garmin Edge, the activities are normally in a folder called Garmin/Activity, as .fit files named after the date and time. Other brands use a similar logic but different folder names, and the layout can change between models and firmware, so if you do not see it, look for the folder that contains files ending in .fit rather than guessing.

Copy the files, do not move them, until you have checked that they open correctly elsewhere.

Getting the original from your account

If the ride has already synced to a platform, you can usually download the original from it. The wording and menus change from time to time, so treat the following as a guide rather than a recipe:

• Garmin Connect (web). Open the activity, then the gear or settings menu in its top corner, and choose Export Original. You get a ZIP archive that contains the .fit file.
• Strava. On your own activity, open the options menu and look for Export Original. This works for activities you uploaded as files or recorded with a device. If you only see a GPX export, the original was not stored, or the activity came from a source that does not provide one.
• Polar Flow. From your diary, open the session and look for the export option, then choose FIT where it is offered. Ask for the original format and not a simplified one.
• Other services. Look for the export or download option of the activity and prefer "original" or FIT over GPX or TCX.

Files that went through a third party before reaching you may have been modified. For instance, FIT files from 2008-2010 downloaded through Strava report their device as "development", because the original manufacturer information was not kept. That is harmless for analysis but explains the odd device name.

Automatic sync with GearWatts

If you do not want to download files by hand, GearWatts can fetch them for you from three platforms. Each one has its own limits:

• Garmin. Uses the Garmin Personal API, which only works for your own account. You paste a personal API key once, the app lists your cycling and multisport activities and downloads the original files. In a triathlon, it takes the longest bike segment.
• Polar. You authorise the app from Polar's own sign-in page, so you never give it your password. Polar's API (AccessLink) only hands over what was recorded after you connected and in the last 30 days: there is no history through the API. To bring older sessions, export them from Polar Flow as FIT and upload them by hand.
• Hammerhead. You authorise the app and it can read your full history, one activity at a time, as FIT files.

As of November 2026, other makers such as Suunto and Coros only offer their API to companies and partners, not to individual riders, so with those devices you export files by hand. In every case the import skips duplicates and rides that look like runs recorded as bike activities (GPS, no power or shifting, low average speed).

Which one should I keep?

Keep the FIT. It is the only format that is a faithful record of your ride, it is smaller than the others, and you can always create a GPX from it when you want to share a route, but never the other way round. Store the originals in a folder by year, back them up, and do not edit them in apps that re-save them (some "cleaning" tools rewrite the file and silently drop fields). If you want to understand what the numbers in a file mean, see normalized power and TSS.

A privacy tip

A ride file contains the exact GPS track, timestamps, and often device information. The first and last points of most rides are your front door. If you share a file publicly, with a forum, a coach you do not know well or a route-sharing site, trim the first and last few hundred metres, or start the share from a point away from home. Many platforms offer privacy zones; do not rely on them for a file you send directly, as they apply only on the site.