What Is a KMZ File? .kmz Format Explained (and How to Open One)

A KMZ file is a ZIP archive containing a KML file plus any images the KML references. The Z stands for zipped. It is the format Google Earth saves and shares by default, which is why most people meet it without ever choosing it.

If you just want to see what is in yours, you can open a .kmz file online here — it unzips in your browser, lists what is inside, and draws the map. Nothing is uploaded and there is nothing to install.

What File Type Is a .kmz File?

Property	Value
Extension	.kmz
MIME type	application/vnd.google-earth.kmz
Full name	Keyhole Markup Language, Zipped
Category	GIS / geospatial vector data
Underlying format	ZIP archive (renaming to .zip opens it)
Standard	OGC KML 2.2
Created by	Google Earth, Google My Maps, GIS and drone software

Because it is a ZIP, a .kmz is compressed binary — opening one in a text editor shows garbage. That is the single most common source of confusion with this file type, and it is why the plain .kml sibling exists.

What Is Inside a KMZ Archive?

Rename any .kmz to .zip, extract it, and you will find:

• doc.kml — the actual geographic data, as plain-text XML. This is the only required entry, and by convention it sits at the root of the archive.
• An images or files folder — optional. Custom placemark icons, ground overlay imagery, and textures for 3D models, referenced from the KML by relative path.
• COLLADA models — optional .dae files, when the KMZ carries 3D geometry such as a building.

That bundling is the entire reason the format exists. A KML can only link to a custom pin icon. Send the KML alone and the recipient sees broken icons; a KMZ carries the images with it, so one file is enough.

The compression is not incidental either. KML is verbose, repetitive XML, which is exactly what ZIP handles best — a KMZ is routinely a fraction of the size of the KML inside it. That matters for email limits and for import caps on services like Google My Maps.

How to Open a KMZ File

Without installing anything: drop it into the online KMZ viewer. The archive is unzipped in your browser, every entry is listed so you can see what the file actually holds, and the placemarks, paths and polygons are drawn on an interactive map. The file never leaves your device.

In Google Earth: the native option — double-click the file, or use File → Open. Google Earth Pro for desktop is free.

In Google My Maps: create a map and import the KMZ. Be aware of the size and feature limits, and that it needs a Google account.

In desktop GIS: QGIS and ArcGIS both read KMZ directly, no extraction step needed.

As a ZIP: rename the extension to .zip and extract it to get at the doc.kml inside. Useful when you need to hand-edit the XML or feed it to a tool that only accepts plain KML.

KMZ vs KML: Which Do You Have?

They hold the same geographic data. KML is the plain-text XML; KMZ is that same XML zipped, with any assets bundled alongside it. Choose KML when you need to read, edit, diff, or script the file, and KMZ when you are sharing it, when it uses custom icons or overlays, or when size matters.

The full breakdown, including a compatibility table and the file-size difference, is in KML vs KMZ.

Converting a KMZ File

KMZ is built for Google Earth, so it is usually the wrong format for anything else. Every converter below takes a .kmz directly, with no unzipping step:

• KMZ to KML — extract the plain XML out of the archive.
• KMZ to GeoJSON — for web mapping with Leaflet, OpenLayers or Mapbox.
• KMZ to Shapefile (SHP) — for QGIS, ArcGIS and desktop GIS.
• KMZ to CSV — to get the placemarks into a spreadsheet.
• KMZ to GPX — to load a route onto a Garmin, phone or bike computer.

Where KMZ Files Come From

• Google Earth — right-click any placemark, path or folder and choose Save Place As. KMZ is the default type.
• Google My Maps — exports offer KML or KMZ; KMZ is typical when the map uses custom icons.
• Drone and survey software — flight paths and survey boundaries, specifically because KMZ bundles reference imagery with the geometry.
• Government and utility data portals — parcel boundaries, zoning, and infrastructure layers published for Google Earth.

Common Problems

• "The file is corrupted." Usually a KMZ that was renamed from something else, or a download that finished incomplete. Try opening it as a ZIP — if that fails too, the archive itself is broken.
• It opens as gibberish text. Expected. It is compressed binary; you want the doc.kml inside.
• A converter rejects it. Many only accept plain .kml. Extract the KML first, or use a converter that accepts KMZ directly.
• Icons are missing after conversion. Bundled images have no equivalent in GeoJSON, Shapefile or GPX, so they are dropped along with the styling.
• My Maps refuses the import. Google My Maps caps layer size and feature count. Split the file, or view it somewhere without those limits.

FAQ

What is a .kmz file?

A ZIP archive containing a KML file (usually doc.kml) plus any icons, overlay images or 3D models it references. It is the default save format of Google Earth.

How do I open a KMZ file?

Use a browser-based viewer such as the GeoDataTools KMZ viewer, which needs no install, or open it in Google Earth, QGIS or ArcGIS. You can also rename it to .zip and extract the KML inside.

What is the difference between KML and KMZ?

KML is plain-text XML. KMZ is that same KML compressed into a ZIP archive, together with any images it references. The geographic data is identical.

Can I open a KMZ file without Google Earth?

Yes. QGIS and ArcGIS read it directly, and browser-based viewers open it with nothing installed at all.

Is a KMZ file just a ZIP file?

Yes. Renaming the extension to .zip and extracting it gives you the KML and any bundled assets.

What MIME type does a KMZ file use?

application/vnd.google-earth.kmz. Plain KML uses application/vnd.google-earth.kml+xml.

Can Google Maps open a KMZ file?

Google My Maps can import KMZ, subject to file size and feature limits and a Google account. Standard Google Maps cannot open one directly.