KML to GeoJSON Converter

KML (Keyhole Markup Language) is an uncompressed XML text file. KMZ is the zipped version — a standard ZIP archive renamed with a .kmz extension. Inside the ZIP, the primary document is always named doc.kml. KMZ files can also bundle associated assets such as custom icon images and ground overlay images into sub-directories, but these assets are not convertible to GeoJSON. This converter handles both formats: KML is parsed directly; KMZ is first unzipped in the browser using JSZip before the KML inside is parsed.

No. When you drop a file, the browser reads it directly from your local disk using the FileReader API. The file contents are kept entirely in browser memory — no network request is made. The JSZip library used to extract KMZ archives is fetched from a public CDN the first time a KMZ file is dropped, but the KMZ data itself never leaves your machine. You can verify this by opening the browser DevTools Network tab while converting a file — you will see no POST request to any server.

No — and this is by design. The GeoJSON specification (RFC 7946) intentionally omits styling. Geometry, coordinates, and feature properties are preserved; Style, StyleMap, IconStyle, and LineStyle elements are discarded. To control the visual appearance of GeoJSON features on a web map, apply styles in your mapping library (for example, Leaflet's L.geoJSON layer options, or Mapbox GL JS style expressions). If you need styling metadata in the output, consider using the Mapbox simplestyle spec which adds reserved property names that some renderers support.

This is very unlikely when converting from KML, because KML always uses WGS 84 (EPSG:4326) with longitude-first, latitude-second coordinate order — the same order required by GeoJSON. If features appear in the wrong location, the most common cause is a KML file that was incorrectly authored with latitude before longitude in its <coordinates> elements (a known bug in some older export tools). You can detect this by checking whether the output appears in the ocean near 0°, 0°. If so, the original KML was malformed — no converter can fix coordinate-swapped input data.

Yes — the converter extracts only the doc.kml entry from the KMZ archive and ignores all other files (image directories, icon folders, overlay assets). The GroundOverlay and PhotoOverlay elements are skipped since they represent raster data which has no GeoJSON equivalent. Only Placemark elements with recognised geometry are included in the output. Any Placemarks without geometry (such as folders used only as labels) are counted in the skipped-feature warning.

The tool enforces a 200 MB input limit. Browser memory is the practical ceiling — the file must fit in RAM along with the parsed XML DOM and the GeoJSON output. For most KML files (point collections, route tracks, boundary polygons) this limit is far above typical file sizes. KML files with tens of thousands of Placemarks are usually under 50 MB. For files larger than 200 MB, use ogr2ogr -f GeoJSON out.geojson in.kml from GDAL — it streams the file and is not memory-limited.

QGIS: Drag and drop the .geojson file onto the QGIS canvas, or use Layer → Add Layer → Add Vector Layer. QGIS 3.x recognises GeoJSON natively and assigns EPSG:4326 automatically.

Mapbox GL JS: Add a GeoJSON source with map.addSource('my-data', {type:'geojson',data:'./out.geojson'}) then add a layer referencing that source. The Mapbox Uploads API also accepts GeoJSON files directly.

Leaflet: Load the file with fetch('out.geojson'), parse the JSON, and pass the result to L.geoJSON(data).addTo(map).