EPSG:3857 — WGS 84 / Pseudo-Mercator

Projected coordinate system · coordinates in metres · World between 85.06°S and 85.06°N.

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EPSG:3857WGS 84 / Pseudo-Mercator

Coordinates in EPSG:4326 — one pair per line

Paste as many as you like: X,Y or X Y or X;Y (optional Z). Columns copied from Excel or a CSV work as-is.

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🔒 Runs entirely in your browser with GDAL WebAssembly — the same PROJ engine used by QGIS, PostGIS, and ArcGIS. Nothing is uploaded. Output units: metre.

Worked example — the centre of this system's area of use: 0, 0 (EPSG:4326 lon, lat) = 0, 0 (EPSG:3857).

EPSG:3857 is Web Mercator (also called Pseudo-Mercator or Spherical Mercator) — the projection behind the map tiles of Google Maps, OpenStreetMap, Bing, Mapbox, MapLibre, and Esri basemaps. Coordinates are X and Y in metres from the intersection of the equator and the prime meridian, with values reaching about ±20,037,508 m at the edges.

It exists for one job: rendering fast, square, world-covering tile pyramids. It is conformal-ish (shapes look right locally) but wildly distorts size at high latitudes — Greenland renders as large as Africa, which is actually about 14× bigger. Use it for display; never for measurement.

EPSG:3857 details

TypeProjected CRS

DatumWorld Geodetic System 1984 ensemble

Unitsmetre

AxesEasting (east) · Northing (north)

Projection methodPopular Visualisation Pseudo Mercator

ScopeWeb mapping and visualisation.

Base CRSEPSG:4326

Area of use

World between 85.06°S and 85.06°N.

WGS84 bounds: -180° to 180° longitude, -85.06° to 85.06° latitude.

Well-known text (WKT2)

Show WKT2 definition for EPSG:3857

PROJCRS["WGS 84 / Pseudo-Mercator",BASEGEOGCRS["WGS 84",ENSEMBLE["World Geodetic System 1984 ensemble",MEMBER["World Geodetic System 1984 (Transit)"],MEMBER["World Geodetic System 1984 (G730)"],MEMBER["World Geodetic System 1984 (G873)"],MEMBER["World Geodetic System 1984 (G1150)"],MEMBER["World Geodetic System 1984 (G1674)"],MEMBER["World Geodetic System 1984 (G1762)"],MEMBER["World Geodetic System 1984 (G2139)"],MEMBER["World Geodetic System 1984 (G2296)"],ELLIPSOID["WGS 84",6378137,298.257223563,LENGTHUNIT["metre",1]],ENSEMBLEACCURACY[2.0]],PRIMEM["Greenwich",0,ANGLEUNIT["degree",0.0174532925199433]],ID["EPSG",4326]],CONVERSION["Popular Visualisation Pseudo-Mercator",METHOD["Popular Visualisation Pseudo Mercator",ID["EPSG",1024]],PARAMETER["Latitude of natural origin",0,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8801]],PARAMETER["Longitude of natural origin",0,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8802]],PARAMETER["False easting",0,LENGTHUNIT["metre",1],ID["EPSG",8806]],PARAMETER["False northing",0,LENGTHUNIT["metre",1],ID["EPSG",8807]]],CS[Cartesian,2],AXIS["easting (X)",east,ORDER[1],LENGTHUNIT["metre",1]],AXIS["northing (Y)",north,ORDER[2],LENGTHUNIT["metre",1]],USAGE[SCOPE["Web mapping and visualisation."],AREA["World between 85.06°S and 85.06°N."],BBOX[-85.06,-180,85.06,180]],ID["EPSG",3857]]

Frequently asked questions

Why does QGIS say EPSG:3857 is "not suitable for distance measurements"?

Because it is true. Web Mercator preserves angles, not distances or areas: scale stretches with latitude, so one "metre" of EPSG:3857 Y-distance at 60°N covers only about half a real metre of ground. QGIS shows this warning whenever your project CRS is 3857 and you use the measure tool. For real distances, measure geodesically on WGS 84 or reproject to a local CRS such as a UTM zone.

What units is EPSG:3857 in?

Metres — but "Web Mercator metres", which only match ground metres at the equator. At latitude φ, ground distance is approximately the coordinate distance × cos(φ). At 45° the map metre is about 71% of a ground metre; at 60° about 50%.

How do I convert EPSG:3857 to EPSG:4326 (lat/long)?

Paste your X/Y metre values into the converter on this page with the other side set to EPSG:4326, or use our dedicated Web Mercator ↔ WGS84 converter. A tell-tale sign coordinates are 3857: absolute values in the millions.

What is the difference between EPSG:3857 and EPSG:900913 or EPSG:102100?

They are the same projection under different historical names. 900913 was the informal "Google" code used before EPSG standardised it; 102100 is the Esri identifier. Modern software should always use EPSG:3857.

What is the valid range of EPSG:3857?

X and Y each run from about −20,037,508.34 m to +20,037,508.34 m, covering longitudes ±180° and latitudes ±85.06°. The poles cannot be represented at all — the Mercator projection puts them at infinity.