Text, Data & Code tool
GeoJSON ↔ KML Converter
Batch-convert GeoJSON and KML points, lines and polygons into 2D map files. Review conversion notes and download individual results or a ZIP, all in your browser.
Move your map data between formats.
Convert local files privately. Points, lines, polygons with holes, and multi-geometries are supported. This first release creates 2D output.
Up to 10 files · 2 MB each · 10 MB total. UTF-8 text only. No KMZ, projected coordinates, network links, overlays, models or timed tracks. No map tiles or external links are loaded.
Keep your originals. This is a format converter, not a GIS validator or survey tool. Output uses ordinary JavaScript numeric precision; it does not reproject coordinates or verify boundary accuracy. No branding fields are inserted into map data.
Processed privately in your browser — your entries are not uploaded.
Good to know
How this tool works
Choose a conversion direction and open one or more mapping files. Convert them, review the results and acknowledge any warnings before downloading individual outputs or a ZIP. Failed files are listed separately and are not included in the ZIP.
Frequently asked questions
What is GeoJSON ↔ KML Converter useful for?
Convert mapping files privately, with clear notes about any changes. Validate a small sample before processing important data, and keep a copy of the original input.
Is my information stored?
Your text is processed locally in a browser worker. It is not uploaded by this tool or saved in browser storage. Clear releases the working input and result. Downloads remain in your normal download folder.
What data is supported?
WGS84 longitude/latitude points, lines, closed polygons with holes, multi-geometries and geometry collections. GeoJSON FeatureCollections, Features and bare geometries are accepted. KML 2.2 ordinary placemarks are converted. Output is 2D: heights are omitted with a warning. Up to 2,000 features and 50,000 coordinate positions per file.
What may change or be lost?
KML folder hierarchy is flattened. Styling, time information, display settings, IDs and other unsupported metadata can be omitted and reported. KML ExtendedData values import as strings; non-string GeoJSON properties export as JSON text. Boundary winding may be reversed to follow the destination convention. Keep your original files; this is not a lossless round trip.
Are coordinates or boundaries verified?
Coordinate ranges and basic structure are checked, but topology, self-intersections and real-world accuracy are not. Projected coordinate systems and boundaries crossing the antimeridian are rejected instead of guessed. Use a GIS application for those cases. Ordinary JavaScript number precision applies.
Does it open links or upload my locations?
No. Files are processed by a local worker, with a ten-second processing limit per job. Network-linked KML, DTD/entity declarations, overlays, models, timed tracks and KMZ archives are rejected. File contents are not sent to a map service or rendered as HTML.
Format references: GeoJSON specification and KML reference.