KML vs KMZ: What Is the Difference?
KMZ is simply a ZIP-compressed KML file. Both formats contain the same geographic data and are supported by the same tools, but they behave differently when it comes to file size, human readability, and the ability to bundle additional resources like images. Here is a full breakdown.
Bottom line
Use KMZ for sharing and distribution; use KML when you need to read or edit the file as plain text.
KML vs KMZ: feature comparison
| Feature | KML | KMZ |
|---|---|---|
| Format | XML plain text | ZIP archive containing KML |
| File extension | .kml | .kmz |
| File size | Larger | ~70–80% smaller (compressed) |
| Human readable | Yes (open in any editor) | No (needs ZIP extraction) |
| Embedded resources | No (external links only) | Yes (images, icons bundled) |
| Google Earth | Yes | Yes |
| Google My Maps | Yes | Yes |
| Email attachments | Less convenient (larger) | More convenient (smaller) |
| Git version control | Yes (text-diffable) | No (binary diff) |
| Programmatic edit | Easy (any text tool) | Requires ZIP library |
KMLWhen to use KML
- Generating KML programmatically and writing to file directly
- Version-controlling geographic data in git (line-level diffs)
- Inspecting or editing the raw XML without unzipping
- Automated pipelines where text manipulation is required
KMZWhen to use KMZ
- Distributing files to end users via email or download link
- When the KML references embedded images or custom icons
- Uploading to Google My Maps (recommended format for imports)
- Reducing storage and bandwidth when hosting files on a server
Convert between KML and KMZ
Frequently asked questions
Q.How do I convert KMZ to KML?
Rename the .kmz file to .zip and extract it — the doc.kml file inside is the KML. Alternatively, upload the KMZ to Maparz and convert to KML directly.
Q.Can I convert KMZ to GeoJSON?
Yes. Maparz accepts .kmz files directly. Upload your KMZ and select GeoJSON (or Shapefile, GeoPackage, GPX, etc.) as the output format.
Q.Why does KMZ bundle images but KML does not?
KML references external images via URLs. KMZ wraps everything into a ZIP archive, so it can bundle the images alongside the KML file — making the package self-contained.
Q.Which format does Google My Maps prefer?
Google My Maps accepts both KML and KMZ, but KMZ is often recommended because it preserves embedded icons and is smaller. Both formats import the same geographic data correctly.