Free online GPX to FIT converter

A Garmin, Wahoo, or other training device may require a FIT file when a GPX track cannot be imported directly. Converting it also produces a smaller binary file, but it cannot recreate heart-rate, power, cadence, or other sensor data that was never present in the GPX.

What the GPX format is

GPX, or GPS Exchange Format, is an XML-based format for exchanging geographic data between mapping and navigation applications. A GPX file can contain tracks made of recorded points, routes made of planned points, and waypoints such as shops, climbs, or aid stations.

Garmin Connect, Strava, Komoot, Ride with GPS, Gaia GPS, QGIS, and many phone navigation apps can create or export GPX files. You commonly encounter GPX when downloading a route from a website, moving a recording between mapping programs, or archiving GPS data in a readable format. Because GPX is text-based XML, it can be inspected or edited with a text editor, although changing coordinates manually can easily corrupt the file.

What the FIT format is

FIT, or Flexible and Interoperable Data Transfer, is a compact binary format developed for activity and device data. Garmin, Wahoo, Suunto, and other fitness platforms use it for workouts, recorded activities, courses, device settings, and sensor measurements.

FIT can store structured records such as timestamps, latitude, longitude, elevation, speed, distance, heart rate, cadence, power, laps, and device metadata. Its binary encoding is usually smaller than equivalent GPX XML and is better suited to repeated activity records and device synchronization. FIT is useful when a watch, bike computer, or training platform accepts FIT but rejects GPX, or when an activity must retain FIT-specific record structure.

How to convert GPX to FIT

The built-in converter on 101convert.com can perform the conversion without installing software.

1. Keep a copy of the original route.gpx file; conversion does not modify it.
2. Open the GPX-to-FIT converter on 101convert.com.
3. Upload or select route.gpx.
4. Choose FIT as the output format and start the conversion.
5. Download the resulting file, usually with a .fit extension, and rename it only if necessary.

If the converter offers an output category, select course or route when the destination device needs a planned route for navigation. Select activity only when the FIT file is intended to appear as a recorded workout. A FIT activity file and a FIT course file can contain similar coordinates but are not interchangeable in every device workflow.

Before transferring the result, open it in the receiving platform or device software and check the map, distance, elevation profile, and point order. For a Garmin device, the required import method and folder can vary by model; some devices accept course files through Garmin Connect, while others support manual copying to a device course folder.

Quality, compatibility, and limitations

A GPX-to-FIT conversion maps available GPX fields into FIT records. Coordinates, timestamps, elevation, and sometimes speed or distance can be transferred, but GPX usually does not contain the original device's heart rate, power, cadence, temperature, battery, laps, training effect, or sensor identifiers. The converted FIT therefore cannot reproduce an original activity with data that the GPX omitted.

GPX tracks often contain irregular timestamps, duplicate points, missing elevations, or very dense point sequences. The converter may preserve those values, interpolate missing fields, or reduce the number of points. Point reduction can make a file smaller but may remove sharp turns or short route segments, so inspect technically important courses after conversion.

FIT uses defined message types and device profiles, and some older devices accept only a limited subset of FIT fields. A file that validates as FIT may still fail to import if it is encoded as an activity instead of a course, uses unsupported metadata, exceeds device limits, or contains invalid timestamps. If the device rejects the file, try exporting the GPX as a simpler track, remove unnecessary waypoints, ensure timestamps are valid, and select the device's required course or activity type.