Compare coordinate reference systems
Side-by-side comparisons of the coordinate reference systems people most often have to choose between — what each is, how they differ, and what converting between them involves.
- EPSG:4326 vs EPSG:3857 — WGS 84 vs Web Mercator
EPSG:4326 (WGS 84) stores positions as longitude and latitude in degrees on the globe — it is the CRS of GPS, GeoJSON and almost all data interchange. EPSG:3857 (Web Mercator) projects those same positions onto a flat square in meters so they can be sliced into the 256×256 tiles that Google Maps, Mapbox, OpenStreetMap and Leaflet render. They share the WGS 84 datum, so the underlying positions match — but the numbers are completely different: degrees in 4326, meters in 3857. Web Mercator also distorts area badly toward the poles (Greenland looks the size of Africa) and is clipped at roughly ±85° latitude. - EPSG:4326 vs EPSG:4258 — WGS 84 vs ETRS89
Both EPSG:4326 (WGS 84) and EPSG:4258 (ETRS89) are geographic CRSs expressed as longitude/latitude in degrees, so the numbers look the same and most software treats them interchangeably. The difference is the datum's reference frame: WGS 84 is global and tracks the whole Earth, while ETRS89 is fixed to the stable part of the Eurasian tectonic plate. Because that plate drifts a few centimeters per year, WGS 84 and ETRS89 coordinates for the same European point slowly diverge — they were defined as coincident in 1989 and are now offset by a few tens of centimeters. For web mapping the difference is negligible; for surveying or centimeter-accurate work in Europe it is not. - EPSG:4326 vs EPSG:2154 — WGS 84 vs RGF93 / Lambert-93
EPSG:4326 (WGS 84) is global longitude/latitude in degrees. EPSG:2154 (RGF93 / Lambert-93) is the official projected CRS for mainland France and Corsica: a Lambert Conformal Conic projection in meters, designed so a single grid covers the whole country with controlled distortion. Coordinates look entirely different — a Paris point is about (2.35, 48.85) in 4326 but around (652000, 6862000) meters in 2154. Lambert-93 lets you measure distances and areas directly in meters across France; WGS 84 degrees do not have a constant ground distance, so they're poor for measurement but ideal for interchange. - EPSG:4326 vs EPSG:27700 — WGS 84 vs British National Grid
EPSG:4326 (WGS 84) is global longitude/latitude in degrees. EPSG:27700 (OSGB36 / British National Grid) is the Ordnance Survey grid for Great Britain: a Transverse Mercator projection in meters, on the older OSGB 1936 datum. The British National Grid does not share WGS 84's datum, so converting between them needs a datum shift as well as a projection change — and the OSGB36 datum differs from WGS 84 by up to ~100+ meters in places, so ignoring the shift produces a large, location-dependent error. A London point is about (-0.13, 51.51) in 4326 but around (530000, 180000) meters in 27700. - EPSG:25832 vs EPSG:4326 — ETRS89 / UTM 32N vs WGS 84
EPSG:25832 (ETRS89 / UTM zone 32N) is the standard projected CRS for Germany and neighbouring central-European countries between 6°E and 12°E: a Universal Transverse Mercator projection in meters on the ETRS89 datum. EPSG:4326 (WGS 84) is global longitude/latitude in degrees. Because ETRS89 is the European realization of a WGS 84-like frame, the datum difference is only a few centimeters — but the projection difference is total: a Cologne point is about (6.96, 50.94) degrees in 4326 versus around (356000, 5645000) meters in 25832. UTM 32N gives near-true distances and areas in meters within its zone, which is why German official data uses it. - EPSG:4326 vs EPSG:25832 — WGS 84 vs ETRS89 / UTM 32N
EPSG:4326 (WGS 84) is global longitude/latitude in degrees — the default for interchange, GeoJSON and GPS. EPSG:25832 (ETRS89 / UTM zone 32N) is the projected grid in meters used across Germany and central Europe between 6°E and 12°E. The datums (WGS 84 and ETRS89) agree to within a few centimeters, but the units and numbers are entirely different: degrees versus meters. You'd choose 4326 to keep data portable and global, and 25832 to measure distance or area in meters or to match German official datasets. Moving between them is a reprojection, not a relabel.