Web Mercator Converter
Convert coordinates between WGS84 (EPSG:4326) and Web Mercator (EPSG:3857). Used by Google Maps, OpenStreetMap, and most web mapping services.
Input: Longitude / Latitude in decimal degrees (WGS84 / EPSG:4326)
What is Web Mercator (EPSG:3857)?
Web Mercator is the coordinate system used by Google Maps, OpenStreetMap, Bing Maps, and most web mapping services. Coordinates are in metres from the origin (0,0) at the intersection of the Equator and Prime Meridian. The valid range is ±20,037,508 metres in both X and Y.
EPSG:4326 (WGS84) uses longitude/latitude in decimal degrees and is the standard for GPS coordinates, GeoJSON, and most geospatial data exchange formats.
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What is Web Mercator?
Web Mercator (EPSG:3857) is the projected coordinate system used by virtually all web tile map services — OpenStreetMap, Google Maps, Bing Maps, Mapbox, and Esri basemaps all deliver tiles in Web Mercator. It represents positions as X and Y values in metres, measured from the origin at the intersection of the equator and the prime meridian.
WGS 84 (EPSG:4326) is the geographic coordinate system that uses longitude and latitude in degrees. It is the native system for GPS receivers and the standard for data exchange between GIS applications. Converting between the two is necessary whenever you move data between a web tile layer and a GIS that uses geographic coordinates.
Common use cases
Web map development
Convert WGS 84 coordinates from a database to Web Mercator for use with tile layer APIs, or reverse-convert map click coordinates for database queries.
Debugging coordinate mismatches
Diagnose why features appear in the wrong location by checking whether coordinates were mistakenly used in the wrong CRS.
Mapbox GL and Leaflet integration
Convert between the EPSG:3857 coordinates returned by map events and the WGS 84 coordinates expected by GeoJSON and spatial databases.
GIS data preparation
Convert Web Mercator data from a web service to WGS 84 before importing into a GIS for measurement or overlay operations.
Frequently asked questions
Why do Web Mercator coordinates look so large?
Web Mercator (EPSG:3857) coordinates are in metres from the origin at the intersection of the equator and the prime meridian. London's City Hall, for example, has coordinates of approximately X = −11,300 m, Y = 6,710,000 m — the Y value is 6.7 million metres north of the equator.
When should I use Web Mercator vs WGS 84?
Use WGS 84 (EPSG:4326) for data storage, exchange, and any calculation that needs geographic accuracy across large areas. Use Web Mercator (EPSG:3857) when working with web tile services (OpenStreetMap, Google Maps, Mapbox) — those services deliver tiles in Web Mercator.
Does Web Mercator distort distances and areas?
Yes — Web Mercator preserves angles (conformal) but significantly distorts distances and areas at high latitudes. Greenland appears the same size as Africa on a Web Mercator map, even though Africa is about 14 times larger. Never use Web Mercator coordinates for area or distance measurements.
What is the valid range of Web Mercator coordinates?
Web Mercator covers longitudes from −180° to 180° (X: approximately −20,037,508 to 20,037,508 metres) and latitudes from approximately −85.05° to 85.05° (Y: approximately −20,037,508 to 20,037,508 metres). Polar regions beyond ±85.05° latitude are not representable.