KML vs GPX: Which to Use (and How to Convert Free)

KML and GPX both describe geographic data, but they grew up in different worlds. Knowing the difference saves a lot of "why does my track look weird in Google Earth?" frustration.

The one-line summary

• GPX is the universal exchange format for GPS devices and fitness apps.
• KML is Google's format, optimized for visualization in Google Earth and Google Maps.

Where each format wins

GPX is better for:

• Recording activities (running, cycling, hiking)
• Time-stamped tracks with elevation
• Importing into Garmin, Wahoo, Strava, Komoot
• Lightweight files

KML is better for:

• Styled overlays (custom icons, colored polygons, info bubbles)
• Sharing maps with non-technical viewers in Google Earth
• Embedding rich HTML descriptions on points
• 3D buildings, time animations, and ground overlays

What gets lost in conversion?

When you convert KML → GPX:

• Custom styles, colors, and icons are dropped (GPX has no styling).
• HTML descriptions become plain text.
• Polygons can be approximated as tracks but are not a native GPX concept.

When you convert GPX → KML:

• Time stamps are preserved.
• Tracks become `<LineString>` placemarks.
• Default styling is applied; you can edit it later in Google Earth.

How to convert

The free KML ↔ GPX Converter handles both directions in batch and runs entirely in your browser. Drag in a folder, the tool auto-detects each file's format, and gives you the opposite format as a download.

For programmatic conversion, the open-source togeojson library is another option.

Related guides

• Edit a GPX file in your browser
• GPX photo sync workflow
• What is a geotag?

Pick the format that matches the destination tool, and don't be afraid to convert — most lossy bits don't matter for everyday use.