How to convert GPX to KML or KMZ
- Drop the .gpx file and check the preview, which shows the track and its waypoints.
- Pick KML or KMZ: KML when you want to edit or restyle the file, KMZ when a long track log should travel as one small attachment.
- Convert, download, and open the result in Google Earth.
What changes when you convert GPX to KML or KMZ
| What | GPX → KML | |
|---|---|---|
| Geometry | Kept | Waypoints become point features and tracks and routes become lines. GPX has no polygon type, so there are no polygons to carry. |
| Attributes | Changes | GPX stores a fixed set of fields per feature (name, comment, description, symbol, type, elevation, time and a few GPS quality values), and those become attribute fields in KML. Heart rate, cadence and other app extensions are not carried. |
| Styling & labels | Changes | KML supports styling; features are written with clean default styling and a name label you can restyle in Google Earth. |
| Coordinate system | Kept | Both formats are fixed to WGS84 longitude/latitude (EPSG:4326), so the coordinates are copied across without any reprojection. |
| Elevation (Z) | Kept | 3D Z values carry from GPX into KML wherever the source records them. |
| File structure | Kept | A single, self-contained .kml file you can move around on its own. |
| KMZ instead of KML | Kept | Identical content zipped into one .kmz: the same placemarks, attributes and coordinates, usually several times smaller, and a single attachment to email. |
Why convert GPX to KML or KMZ?
GPX is what GPS receivers and fitness apps write, built for navigation rather than for showing a route on satellite imagery. KML is the format Google Earth draws from, and KMZ is the same document zipped into one small file, so either output turns a recording into a path draped over terrain. A recording can also hold both a planned route and the track you actually followed. In Google Earth the two arrive as separate items, so you can lay the plan over the ride and use the waypoints as markers to see where the day went off script.
Coordinate system handling
GPX records every point in WGS84, the way GPS receivers do, and KML and KMZ are fixed to WGS84 by the Google Earth specification, so no reprojection happens in either direction. The longitude and latitude written by your device are the numbers in the output.
What to check when converting GPX to KML or KMZ
Check your attributes before relying on them in Google Earth. GPX carries a fixed set of fields, so heart rate, cadence and other app extensions are not carried into KML or KMZ, and may already be simplified in the source file. GPX stores tracks as ordered points that become paths, so confirm your waypoints, routes and tracks all landed as the right geometry rather than merged into one line. Keep the original GPX if you need the full time series, because per-point timestamps have no slot in standard KML geometry.
Troubleshooting GPX to KML or KMZ
- Heart rate and cadence are missing in Google Earth. Those are GPX extension fields with no slot in KML, so they are not written. Keep the original GPX alongside the converted file for the full sensor record.
- The KMZ arrives as a .zip or will not open from a mail app. Some mail and chat apps treat a .kmz as a plain zip and rename or block it. Rename the attachment back to .kmz, share it through a file link, or send the KML instead.
- The first minutes of the track wander or sit off the trail. A receiver with a poor fix can log a scattered start before it settles, and the conversion preserves that recording as it is. Trim or clean the opening stretch in your sports app, then convert again.
About the formats
A GPX file is what your watch or handheld records after a hike, run or ride: waypoints, a planned route and the track you actually followed, always in WGS84. KML is how Google Earth draws that same line over satellite imagery, and KMZ is the KML zipped into one archive that opens with a double-click. All three are plain-text XML underneath, so the coordinates carry across without reprojection; a track log of thousands of points also compresses well, which is why in the site's 10,000-point benchmark the KMZ came out about 16 times smaller than the raw KML.
Frequently asked questions
Why does the path sit flat on the ground in Google Earth?
Elevation carries over only where the trackpoints recorded it. Routes planned by hand have none, so Google Earth clamps the line to the ground.
The track looks jagged near buildings, so did the conversion do that?
No. GPS scatter is preserved point for point, so clean the track in your sports app first if you want a smooth line.
Only the waypoints show up, so where did the track go?
Expand the entry in the Google Earth sidebar, because waypoints, routes and tracks sit in separate folders there. Toggle each folder before assuming anything was dropped.
Should I choose KML or KMZ for my track?
Choose KML when someone may open the file in a text editor, restyle the path, or load it into QGIS or a web tool. Choose KMZ when the recording is going out by email or chat, since the zipped file is far smaller and Google Earth opens it directly; both versions carry identical paths and placemarks.
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