KML vs. KMZ: Key Differences, File Sizes & When to Use Each
KML is the plain-text XML format that stores points, lines, and polygons for Google Earth. KMZ is a zipped KML—same data plus images and icons bundled into one compressed file.
People scratch their heads because both open in Google Earth, so the difference feels invisible until email bounces with “file too big” or the map loads without custom icons.
Key Differences
KML is human-readable text; open it in Notepad and edit coordinates. KMZ is a zipped archive that shrinks large overlays and keeps external images together, cutting file size by 60-90 %.
Which One Should You Choose?
Use KML for quick edits and small datasets under 1 MB. Choose KMZ for anything with custom icons, photos, or when sharing via email, WhatsApp, or slow connections.
Can I rename .kmz to .zip and extract it?
Yes—KMZ is a standard ZIP archive. Rename, unzip, and you’ll find the original KML plus any resource folders.
Does Google Earth open both KML and KMZ identically?
It renders them the same, but KMZ loads faster and keeps external links intact, avoiding broken icons.
When does file size decide the format?
Anything over 1 MB or needing embedded images should be KMZ; otherwise, plain KML keeps things lightweight and editable.