Convert KML to KMZ
Pack a KML into a KMZ for sharing. This is the one conversion where absolutely nothing is lost: your file is placed into the archive byte for byte, so every name, description, folder and style is exactly as you left it. Typical files come out 80–95% smaller.
Drop your KML here
or
Your file is converted inside this tab and never uploaded. No size limit, no sign-up.
What happens to your data
KML and KMZ store different things, so some parts of your file translate exactly and others cannot. Here is the whole picture before you convert, rather than after.
Everything in your fileKept
The KML is stored in the archive unchanged, not re-written. There is no parsing step that could reinterpret or drop anything.
File sizeChanged
KML is XML, which compresses extremely well. Expect the KMZ to be a small fraction of the original, often under a tenth.
Styling and foldersKept
Colours, icon references, line widths and your folder structure all survive, because none of it is touched.
Custom icon imagesChanged
A KMZ can hold images alongside the KML, but a plain KML has none to carry. Icons that point at web addresses keep working as before.
Coordinate systemKept
Both formats are WGS 84 longitude and latitude. No coordinates are read, changed or rounded.
How to convert KML to KMZ
- 1
Choose your KML file
Drag a .kml onto the box above. It stays on your computer; nothing is sent anywhere.
- 2
Convert
The file is checked so a damaged KML is caught early, then packed into the archive exactly as it is.
- 3
Download the KMZ
You get one .kmz file, with the size saving shown so you can see what the compression bought you.
- 4
Share or open it
Double-click to open in Google Earth, or attach it to an email. KMZ is the format Google Earth itself saves by default.
KMZ is just a zipped KML
There is no difference in what the two formats can express. A KMZ is a standard zip archive containing a file called doc.kml at its root, optionally with images beside it for custom icons and overlays. Google Earth reads both identically.
That is why this conversion can be perfectly lossless. Converting between most formats means reading data into one model and writing it out in another, and anything the target cannot express gets dropped. Here there is no translation at all: the bytes of your KML go into the archive untouched.
Why the file gets so much smaller
KML is XML, and XML is extremely repetitive: the same tag names appear thousands of times, and coordinates are stored as plain decimal text. Compression algorithms thrive on exactly that kind of repetition.
A KML with a few thousand placemarks can easily drop from 20 MB to under 1 MB. That is the difference between an attachment that bounces off a mail server and one that goes through without comment.
When to use which
Use KMZ for anything you are sending to someone else, or storing. It is smaller, it is a single file even when custom icons are involved, and it is what Google Earth saves by default.
Use KML while you are working on the file. It is plain text, so you can open it in any editor, search it, fix a coordinate by hand or generate it from a script. Many GIS tools also read KML more readily than KMZ.
Because converting between the two loses nothing in either direction, there is no cost to switching whenever it suits you.
Nothing is uploaded
The zipping happens in your browser. Your KML is never sent to a server, so there is no file size limit and no copy of your data anywhere else.
This matters more than usual for a compression step, because the files people compress are typically the big ones they are about to share, and those are often the sensitive ones.
KML and KMZ, briefly
KMLKeyhole Markup Language
The XML format Google Earth uses. One readable text file that holds points, lines and polygons together with their names, descriptions and colours.
KMZZipped Keyhole Markup Language
A KML file and its images, icons and overlays packed into a single zip with a .kmz extension. Smaller to send, and the one file carries everything it needs to draw.
Questions people ask
Does converting KML to KMZ lose any data?
No, nothing at all. Your KML is placed inside the archive exactly as it is, without being parsed and rewritten. Every placemark, description, folder, style and coordinate is bit-for-bit identical to the file you started with. This is the only common geospatial conversion that is completely lossless.
How much smaller will my KMZ be?
Usually between 80% and 95% smaller. KML is XML, which repeats the same tag names constantly and stores coordinates as plain text, so it compresses very well. A 20 MB KML commonly becomes well under 1 MB. The exact saving is shown with your result.
What is the difference between KML and KMZ?
A KMZ is a zip archive containing a KML file named doc.kml, plus any images it needs for custom icons or overlays. They describe exactly the same things and Google Earth opens both. KMZ is smaller and bundles images into one file; KML is readable text you can edit directly.
Can I just rename my .kml to .kmz?
No. The extension is not what makes a KMZ; the file has to actually be a zip archive containing the KML. Renaming it produces a file Google Earth will refuse to open. Converting it properly, as this tool does, creates a real archive.
Is my file uploaded anywhere?
No. The archive is created in your browser using the browser's own compression, so your file never leaves your computer. There is no upload step, which is also why there is no size limit.
Will my custom icons still work in the KMZ?
Icons that reference a web address keep working exactly as they did, since the link is unchanged. Icons that referenced an image file sitting next to your KML on disk will not be found, because that image was never part of the KML itself. To bundle local images, build the archive with them included.
Can I convert the KMZ back to KML later?
Yes, and you will get your original file back unchanged, since it was only ever stored rather than rewritten. Use the KMZ to KML converter for that.
Is KMZ supported everywhere KML is?
Google Earth and Google Maps handle both without issue, as do QGIS and ArcGIS. A few simpler tools and web viewers only accept plain KML, in which case convert back the other way first. If you are generating files for an unfamiliar system, KML is the safer choice.
Other conversions
Need a combination that is not listed? The universal converter handles every format this tool reads and writes.