A KMZ is a ZIP archive containing a KML document and its images. This extracts the document — unchanged, byte for byte — because nothing about it needs converting.
This is not really a conversion
doc.kml) plus any icons and overlay images the map uses. Google Earth exports KMZ by default because it keeps a map and its pictures together in one file.
Nothing is reformatted here: the XML that comes out is exactly the XML that went in. That is worth knowing because it means nothing can be lost in the step.
You could do the same by renaming the file to .zip and unzipping it. This is faster, tells you what else was in the archive, and handles the cases where the KML is not named doc.kml.
What stays behind
If the map's appearance matters, keep the KMZ. If you want the data — to convert onward to GPX or GeoJSON — the KML is what you need, and you can convert straight from the KMZ on those tool pages without this step.
When a KMZ will not open
Other names for this
Also searched as “unzip kmz”, “extract kml from kmz”, “kmz to google earth”.
Questions
- Can I just rename it to .zip?
- Yes — a KMZ is a ZIP. This does the same thing, tells you what else was inside, and copes when the KML is not named doc.kml.
- My custom icons no longer show.
- They were separate images in the archive and are not extracted. The KML still references their paths. Keep the KMZ if the appearance matters.
- Do I need this before converting to GPX?
- No. The GPX and GeoJSON tools accept a KMZ directly.
- Is my file uploaded?
- No. Everything runs in this tab. That matters more here than almost anywhere else on the site — a calendar is your movements, an address book is other people’s personal data, and a GPS track is where you live and where you run. None of it is sent anywhere.