Convert KML to KMZ and shrink a bulky Google Earth file into one compressed attachment. The zip is produced right in the tab; since KML is plain text, the size drop is usually dramatic.
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KML, KMZ, SHP (.zip), GeoJSON, GPKG, GML, GPX, DXF, CSV, Excel, and more
No KML file to hand? Download a sample KML file (100 points) and drop it above to see the conversion.
Every format stores different things, so a conversion is never perfectly loss-free. Here is exactly what carries over when you convert KML to KMZ, and what to watch for.
| What | KML → KMZ | |
|---|---|---|
| Geometry | Kept | Points, lines and polygons are preserved exactly, including multi-part shapes. |
| Attributes | Kept | Every column and full field name moves from KML into KMZ untouched. |
| Styling & labels | Kept | Neither KML nor KMZ stores visual styling, so there is nothing to lose, the geometry and data carry straight over. |
| Coordinate system | Changes | KMZ is defined in WGS84 (EPSG:4326), so data is reprojected to lon/lat on the way out. |
| Elevation (Z) | Kept | 3D Z values carry from KML into KMZ wherever the source records them. |
| File structure | Kept | One compact .kmz (a zipped KML), easy to email and quick to open in Google Earth. |
KML is plain XML that Google Earth reads directly, so it is easy to edit and share. However, a detailed KML can grow large, especially with many placemarks, paths and overlays. KMZ fixes that. It packs the same KML into a ZIP archive, so the file shrinks and travels as one piece. People convert KML to KMZ when a map is finished and ready to hand off. For example, you can email a Google Earth map as one small file, or bundle custom icons and ground overlays with your placemarks. KMZ is also what Google Earth exports by default, so it is the natural delivery format.
KML is already defined in WGS84 longitude/latitude (EPSG:4326), so no guessing is needed on the way in.
KMZ is defined in WGS84 (EPSG:4326), so the output is reprojected to longitude/latitude, exactly what Google Earth and web maps expect. A quick CRS check before you download saves the classic "my KML data is in the wrong place" surprise; the guide on coordinate systems and EPSG codes goes deeper.
A KMZ is a ZIP container, not a plain text file. So do not double-click it expecting to read XML. This tool reads your KML, then re-zips it into the KMZ. However, external images or icons your KML links to are not automatically pulled inside. If you want a self-contained KMZ with custom icons or ground overlays bundled in, confirm those assets travel with it. Both formats stay in WGS84 lon/lat, so coordinates do not shift.
KML files typically come out of Google Earth, Google Maps, QGIS, ArcGIS. Once you convert to KMZ, the file opens in Google Earth Pro and Google Earth for web by a simple double-click, plus QGIS and ArcGIS Pro. The KMZ output follows the standard specification exactly, so those programs read it without any special import settings.
KML holds your placemarks, paths and styling as plain XML, which makes it easy to open and edit by hand. KMZ takes that same document and zips it into one compact file. Converting KML to KMZ is really a packaging step. The geometry, labels and folder structure stay identical; you just wrap them for delivery. In practice you author and tweak in KML, then hand off KMZ because it is smaller and travels as a single attachment.
No. KMZ holds the exact same KML inside, still in WGS84 lon/lat, so points, lines, polygons and styling stay intact. The only real change is that the file is now zipped and smaller.
Yes. Google Earth reads KMZ natively, and it is in fact the format Google Earth exports by default. QGIS and ArcGIS can open it too, and Google Maps supports KMZ import.
Yes. The KMZ stores the exact same KML text inside its archive, so icon styles, line colors, labels and folder grouping all carry over unchanged. Zipping changes how the file is packaged, not what it contains. Google Earth reads either one the same way.
Only assets actually packaged with the document end up inside the archive. If your placemarks point to icons by web URL, the KMZ keeps those as links rather than embedding the images. Locally stored icons and ground overlays need to sit alongside the KML to be included.
A KMZ file opens in Google Earth by double-click, plus QGIS and ArcGIS. Because the output follows the standard specification, any tool that supports KMZ will read it without special settings.
No conversion is perfectly loss-free because each format stores different things, but geometry and attributes are preserved; only presentation-level styling (which KMZ does not store) is left behind.
Going the other direction, you can convert KMZ back to KML, or send the same file to a shapefile or a CSV of coordinates. The complete set is on the KML & KMZ converter hub.
