EPSG Code Reference
A searchable reference for the most common EPSG coordinate reference system codes — with proj4 strings, area of use, units, and descriptions for every entry.
Every GIS dataset, spatial database, and mapping API is implicitly tied to a coordinate reference system (CRS). EPSG codes are the industry-standard identifiers for those systems — maintained by the IOGP EPSG Geodetic Parameter Registry.
The EPSG Code Reference covers the codes developers actually encounter — from the ubiquitous EPSG:4326 (WGS 84 / GPS) and EPSG:3857 (Web Mercator) through to national grids, UTM zones, and polar projections.
How to use EPSG codes
| Context | How |
|---|---|
| PostGIS | SELECT ST_Transform(geom, 4326) |
| GDAL / OGR | gdal_warp -t_srs EPSG:3857 input.tif output.tif |
| QGIS | Layer properties → Source → CRS |
| Leaflet | Leaflet uses EPSG:4326 for data, renders in EPSG:3857 |
| Proj4js | proj4('EPSG:27700', 'EPSG:4326', [x, y]) |
[!TIP] Click a proj4 string to copy it directly. The
+proj=...strings are compatible with Proj4js, GDAL, and most GIS tooling.
EPSG Code Reference
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