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TCX to KML Converter
Turn .tcx training files — the format of a decade of Garmin Training Center exports and Strava downloads — into .kml files that render in Google Earth. Laps become separate placemarks and timestamps survive as gx:Track, all converted locally in your browser.
How to convert to KML
- 1
Drop your file
Drag a FIT, GPX, TCX, KML, KMZ or GeoJSON file onto the box above, or click it to browse. The source format is detected automatically from the file contents.
- 2
Wait a beat
The conversion runs in a background worker on your device. Typical activities finish in well under a second; even 50 MB files process without freezing the page.
- 3
Check the preview
Distance, duration, ascent and average heart rate are shown alongside a map of the converted track, so you can confirm nothing was lost before downloading.
- 4
Download
Click the download button and the .kml file is saved straight from memory. Nothing was uploaded, so there is nothing to clean up.
What is a TCX file?
TCX (Training Center XML) is Garmin's older training format, introduced with Garmin Training Center in the mid-2000s and later extended by Strava and others. Like GPX it is XML, but TCX is structured around workouts rather than raw tracks: activities contain laps, laps contain tracks, and the schema natively understands training concepts — total time, distance, calories, heart rate zones and cadence — that plain GPX leaves to extensions.
Today TCX sits between two worlds: modern Garmin devices write FIT, while Strava's uploader still accepts TCX as a first-class citizen and many legacy coaching tools (TrainingPeaks imports, older Polar flows, Golden Cheetah archives) expect it. Converting into or out of TCX is usually about keeping lap structure and summary data intact while crossing between those generations of software.
What is a KML file?
KML (Keyhole Markup Language) is the XML dialect born inside Keyhole — the software that became Google Earth — and later standardized by the OGC. It describes geographic features for display: placemarks, lines, polygons and images, each with the styling and folders that make a KML file read like a curated map rather than a raw data dump. Google Earth, Google My Maps and most desktop GIS packages open it natively.
KML is a mapping format, not a training format. Its geometry carries position and elevation well — and Google's gx:Track extension can even carry per-point timestamps for time-slider playback — but it has no concept of heart rate, cadence or power. Converting an activity to KML is the right move when the goal is showing a route to humans; when the goal is analyzing a workout, the fitness formats are the right home for the data.
Why drag an old TCX library into Google Earth?
TCX archives hold history: years of activities exported from Garmin Training Center, downloaded from Strava, or backed up from coaching platforms. Those files are rich but nearly unviewable without training software. Converting them to KML turns the archive into something anyone can open — every favorite route rendered over real terrain in Earth, ready for a nostalgic scroll through a decade of riding or running.
It's also a rescue path. Training Center is long gone, platforms shut down, and a .tcx that nothing current reads is data at rest; the same track as KML is data in use — on the globe, in My Maps, in a QGIS project about where you actually train. Because TCX is XML carrying timestamps throughout, the conversion keeps the temporal story: Earth's time slider plays back the workout lap by lap.
How the conversion treats TCX structure
TCX activities are built from laps, and the converter honors that: each lap becomes its own placemark in the KML document, in order, so interval sessions and auto-lapped runs stay visibly structured on the globe rather than collapsing into one line. Position, elevation and timestamps convert point for point into gx:Track geometry.
The honest limits are the destination's: KML has no heart rate, cadence, power or calorie concept, so the physiological channels that make TCX a training format are dropped — this is a visualization conversion, not an analysis one. Keep the original TCX files as the archival source of truth; let the KML copies be what you (and others) actually look at.
Your files never leave this browser
This tool — like every tool on this site — runs entirely as client-side JavaScript. The file you drop is parsed in a Web Worker on your own device, converted in memory and handed straight back to you as a download. There is no upload endpoint, no server-side conversion service and no temporary storage: you can watch the network tab in your browser's developer tools and confirm that no file bytes are transmitted anywhere.
That matters more with fitness data than with most files. A GPS track is a precise log of where you were, at what time, and how hard your heart was working — home address, training habits, favorite routes and race schedule all in one file. Keeping conversion on-device means third-party converters never get a copy of that log, and the tool keeps working identically on a plane, in a basement, or anywhere else without signal.
TCX vs KML at a glance
| Aspect | TCX | KML |
|---|---|---|
| Format type | Training XML (Garmin) | Display-oriented XML (Google Earth) |
| Typical use | Training platforms, legacy archives | Visualization in Earth / My Maps |
| GPS + elevation | Yes | Yes |
| Laps | First-class structured laps | One placemark per lap |
| Heart rate / power | Native | Not representable — dropped |
| Best for | Training data fidelity | Making archives viewable |
Frequently asked questions
Yes — one at a time on this page, with no upload and no queue. Batch converting a whole archive in one sitting is exactly what the no-limits, on-device model is for; the browser tab is the only bottleneck.