Free online TCX to KML converter

Fitness watches and training applications commonly export activities as TCX, while Google Earth and many mapping tools use KML for displaying geographic data. Converting the file lets you view a workout on a 3D map, share the route, or edit it in a KML-compatible GIS application.

What the TCX format is

TCX, or Training Center XML, is an XML-based fitness data format originally associated with Garmin Training Center. Garmin watches, Garmin Connect exports, Strava exports, and other training applications can produce TCX files containing activities, courses, laps, trackpoints, timestamps, elevation, distance, heart rate, cadence, calories, and speed.

A TCX file is structured for training analysis rather than general-purpose mapping. It can contain several activities or detailed sensor records, so opening it in a text editor shows XML elements instead of a directly viewable route.

What the KML format is

KML, or Keyhole Markup Language, is an XML format for geographic features. Google Earth, Google Maps tools, QGIS, ArcGIS, and other mapping applications can display KML paths, points, polygons, descriptions, styles, and time-based geographic data.

For a workout, KML normally represents the GPS track as a line using longitude, latitude, and elevation coordinates. It is useful for map viewing, route sharing, geographic annotation, and importing a track into mapping software. KML is generally more suitable for visual presentation than for preserving training metrics.

How to actually convert TCX to KML

Using the converter on 101convert.com

1. Open the TCX-to-KML converter on 101convert.com.
2. Select or upload the .tcx file.
3. Choose KML as the output format.
4. Start the conversion and download the resulting .kml file.
5. Open the result in Google Earth or another KML-compatible application and check the route, elevation, and timestamps if those are required.

This method requires no installed software and is appropriate when the input is a normal activity export and the desired result is a viewable map track.

Using GPSBabel on a computer

GPSBabel can convert many Garmin Training Center TCX files from the command line. After installing it, run:

gpsbabel -i gtrnctr -f activity.tcx -o kml -F activity.kml

Replace activity.tcx with the input filename and activity.kml with the desired output filename. The gtrnctr input driver reads Garmin Training Center XML, while kml writes the geographic result. Open the output with Google Earth or import it into a GIS program.

Using a GIS application

Applications such as QGIS can be used when the route needs further editing. First convert the TCX file with the online converter or GPSBabel, then use Layer → Add Layer or the application’s KML import command to load the resulting file. Save the edited layer as KML through Export → Save Features As, selecting KML as the format.

Quality, compatibility, and limitations

The conversion normally preserves the GPS path, but it may not preserve all TCX training fields. Heart rate, cadence, power, calories, lap boundaries, equipment data, and sport-specific metadata depend on the converter and the KML structure it generates.

Check the coordinate system and route before relying on the result. KML uses WGS 84 geographic coordinates, and a malformed or incomplete TCX file can produce missing points, an incorrect path, or no visible geometry. Indoor activities without GPS coordinates cannot produce a meaningful map track.

KML files can become large when every TCX trackpoint is exported. If the result is slow to open, simplify the track in a GIS application or use a reduced-point export. Some applications support Google Earth’s gx:Track time extensions, while others read only a static LineString; therefore, playback timestamps and elevation profiles may not appear consistently across programs.