Free · Local file processing · No account

Compress KML to KMZ Online

A KML file is too large to email, upload or load comfortably, and you need to see how many bytes the archive saves without simplifying the data.

Loading the local file tool…

How to use this tool

1. Choose the KML files that need to be smaller.
2. Run compression and compare the reported input and output bytes.
3. Download the KMZ and check the result in Google Earth or the KML viewer.

Limits and checks before sharing

Compression repackages the original XML; it does not remove vertices, drop precision or repair geometry. Use KML simplify for vertex reduction.
Already compact files may not shrink, and relative icons, images or models are not bundled, so the saved bytes reflect the XML only.

If processing fails, check the file extension and source contents. Use a smaller batch if memory runs low. The original files are never overwritten. Inspect known locations and attributes before sharing a result.

Frequently asked questions

Why did my KML barely change size?

KMZ is a DEFLATE archive of the same XML. Files that are already compact, or that are dominated by long coordinate lists of random precision, compress poorly without simplification.

Does compression change coordinates or attributes?

No. The original KML bytes are stored as doc.kml in a ZIP archive. Coordinates and attributes are not converted or simplified, so the map renders identically.

Are my files uploaded, and do I need an account?

No. This file operation runs in your browser and needs no account or payment. The page and processing libraries need an initial network load. Opening a map preview can request external map tiles; linked resources in your original KML are not fetched or embedded by this tool.

Continue with your result

Inspect outputs directly using the result button above. Choose a compatible next operation in the result panel to continue locally without downloading again. These related links open a fresh task. Share the downloaded file through your own channels; local files are not published to a hosted URL.