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Processed locally — your file never leaves your device

CRS Converter

Reproject GeoJSON, KML or GPX between coordinate reference systems — WGS 84, Web Mercator, S-JTSK, UTM and more, entirely in your browser.

Drop a GeoJSON, TopoJSON, KML, KMZ, GPX, zipped Shapefile or CSV file hereor click to choose a file from your deviceNothing is uploaded — the file is detected and processed entirely on your device.

How it works

  1. Select or drop a .geojson, .kml or .gpx file.
  2. The source coordinate system is detected automatically when the file declares one — otherwise pick it yourself.
  3. Choose a target CRS: use a quick-select button, search by EPSG code or name, or paste a proj4 definition.
  4. Click Convert CRS, then download the reprojected file. Attributes and geometry types are preserved.

Frequently asked questions

Is my file uploaded anywhere?
No. The transformation runs entirely on your device using proj4, which carries every projection definition it needs locally — no lookup service is ever contacted.
Which coordinate reference systems are supported?
A curated set of global and national systems is built in and searchable by EPSG code, name or alias — including WGS 84 (EPSG:4326), Web Mercator (EPSG:3857), S-JTSK / Krovak East North (EPSG:5514), ETRS89 / UTM zone 33N (EPSG:25833), British National Grid, Lambert-93, RD New and more. For anything not listed, you can paste a proj4 or WKT definition and use that instead.
Can it detect my file's coordinate system automatically?
Yes, when the file declares one. GeoJSON written against the older 2008 spec carries a "crs" member, which is read and used as the source automatically. RFC 7946 removed that member, so many modern files declare nothing — in that case you pick the source yourself rather than the tool guessing, since assuming WGS 84 would silently corrupt a projected file.
Are my attributes and geometry types preserved?
Yes. Only coordinate values change — feature properties, feature ids, geometry types (including GeometryCollection) and ring structure all pass through untouched, and elevation values are carried across unchanged.
Why does the map preview not update for a projected result?
The map can only draw WGS 84 longitude/latitude. When you convert to a projected system the preview keeps showing your input, because drawing projected metre coordinates on a lon/lat map would place them nowhere near the right location. The downloaded file is still correct.