What is the KLM file format?
A .klm file is almost always a .kml file whose extension letters were accidentally transposed - "kml" becoming "klm". There is no independently defined .klm format; the underlying data is Keyhole Markup Language (KML), an XML-based standard for storing and exchanging geographic information such as placemarks, paths, polygons, and image overlays.
KML was created by Keyhole, Inc. and became part of Google when the company was acquired in 2004. KML 2.2 was adopted as an Open Geospatial Consortium (OGC) standard in 2008; version 2.3 followed in 2015. Files are plain UTF-8 XML, beginning with <?xml version="1.0" encoding="UTF-8"?> and a <kml> root element with the namespace http://www.opengis.net/kml/2.2. Coordinates are expressed in WGS 84 as longitude,latitude[,altitude] tuples.
The fix is simple: rename the file from .klm to .kml, then open it in Google Earth Pro, QGIS, or any mapping tool. If the file is compressed, it would use the .kmz extension instead (a ZIP archive containing one or more .kml files).
Before renaming, open the file in a text editor to confirm it begins with <?xml and contains a <kml> element. In rare cases a .klm extension may belong to a completely unrelated application, in which case the XML check will immediately reveal the difference.
Related open geographic formats include .gpx (GPS Exchange Format) and .geojson.
Security & safety
RISK: LOWA .klm file is plain XML with no executable code, so it is safe to open. The only KML caveats apply: a <NetworkLink> element can make the file fetch remote content from a URL when opened (a privacy/tracking vector - be cautious with files from untrusted sources), and shared map data can reveal a home address or routine movements. Confirm the file is really KML by opening it in a text editor before trusting it; if it isn't XML at all, it may belong to a different, unrelated program.
Format details
in a nutshellPrograms that open KLM files
Windows3 apps
Google Earth Pro (desktop)
Free Rename the file from .klm to .kml, then File > Open in Google Earth Pro to load it onto the globe. 
QGIS
Open-source After renaming to .kml, Layer > Add Vector Layer to view it as GIS data and convert it.
Notepad / VS Code
Open-source Open the .klm as text to confirm it's <?xml … <kml …> map data before renaming to .kml. 
macOS2 apps
Linux1 app
Android1 app
Google Earth (app)
Free Rename to .kml and open via the Projects menu to view it on the mobile globe.
Google Earth (web)
Free Rename to .kml, then in earth.google.com use Projects > Import KML file to view it in the browser. Technical details
deep spec| Format nature | Misspelled extension for KML (Keyhole Markup Language); no independent format definition exists - always a transposed spelling of .kml |
| Underlying file type | Plain UTF-8 XML geographic data, identical in structure to a .kml file |
| MIME type | application/vnd.google-earth.kml+xml (same as KML; also accepted as application/xml or text/xml) |
| XML root element | <kml> with namespace http://www.opengis.net/kml/2.2 (KML 2.2) or http://www.opengis.net/kml/2.3 |
| File signature | Starts with <?xml at byte offset 0; <kml followed by a namespace attribute appears in the XML body |
| Coordinate system | WGS 84 - coordinates stored as comma-separated lon,lat[,alt] text tuples inside <coordinates> elements |
| Supported geometry types | Point, LineString, LinearRing, Polygon, MultiGeometry - all expressed as child elements of <Placemark> |
| Document hierarchy | <kml> > <Document> > <Folder> > <Placemark> (or NetworkLink / Overlay at any level) |
| Style elements | <Style> and <StyleMap> blocks control icon image, color, line width, and polygon fill for each feature |
| Overlay types | GroundOverlay (georeferenced image), ScreenOverlay (HUD image), PhotoOverlay (360/panoramic image) |
| Compression | None - this is raw XML; the compressed ZIP-wrapped equivalent uses the .kmz extension |
| Typical file size | A few KB for simple placemarks up to several MB for datasets with many polygons or large coordinate arrays |
| Fix action | Rename the extension from .klm to .kml; no re-encoding or conversion is required |
| KML version declared in file | Set by the xmlns attribute value - typically KML 2.2 (2008 OGC standard) or KML 2.3 (2015) |
| Released | KML: 2004 (Google acquired Keyhole); KML 2.2 became an OGC standard in 2008 |
| Latest version | KML 2.3 (OGC, 2015) - '.klm' is not a separate format, just a transposed spelling of .kml |
| Open standard | Yes · royalty-free |
| Specification | www.ogc.org |
KLM conversions
Community Q&A
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