EPSG:3857 ↔ EPSG:4326 Converter
Convert coordinates between Web Mercator (EPSG:3857) and WGS84 (EPSG:4326) latitude/longitude. The Web Mercator projection is used by Google Maps, OpenStreetMap, Mapbox, and most web map tile 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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EPSG code quick reference
EPSG:3857
Web Mercator (Spherical Mercator)
Projected CRS — X / Y in metres. Used by Google Maps, OpenStreetMap, Bing, Mapbox, and almost every web tile service. Origin at (0°, 0°). Valid range roughly ±20,037,508 m on each axis. Latitude limit ≈ ±85.05°.
EPSG:4326
WGS 84 (World Geodetic System 1984)
Geographic CRS — longitude / latitude in decimal degrees. Native CRS for GPS, GeoJSON, and most data exchange. Longitude −180° to +180°, latitude −90° to +90°. The default CRS to assume when no .prj is specified.
What is EPSG:3857 (Web Mercator)?
EPSG:3857 — also known as Web Mercator, Spherical Mercator, or Pseudo-Mercator — is the projected coordinate system used by virtually all web tile map services. OpenStreetMap, Google Maps, Bing Maps, Mapbox, MapLibre, and Esri basemaps all deliver tiles in EPSG:3857. It represents positions as X and Y values in metres, measured from the origin at the intersection of the equator and the prime meridian.
EPSG:4326 — WGS 84 — 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 EPSG:3857 and EPSG:4326 is the single most common projection task in modern GIS and is what this tool exists to do.
Quick conversion examples
Common cities, paired in both directions. Useful as a sanity check that your conversion math is right, or for quick lookups.
| Location | EPSG:4326 (lon, lat) | EPSG:3857 (X m, Y m) |
|---|---|---|
| Null Island (origin) | 0.0000, 0.0000 | 0.00, 0.00 |
| London (Trafalgar Sq.) | −0.1281, 51.5074 | −14,256.00, 6,711,533.71 |
| New York (Times Sq.) | −73.9857, 40.7484 | −8,236,253.45, 4,975,131.66 |
| Tokyo (Shibuya) | 139.7008, 35.6586 | 15,551,488.66, 4,253,818.69 |
| Sydney (Opera House) | 151.2153, 33.8568 | 16,832,909.62, 4,015,255.43 |
| Web Mercator extent edge | ±180.0000, ±85.0511 | ±20,037,508.34, ±20,037,508.34 |
At zoom level 0 the Web Mercator world spans 256 × 256 pixels, which is roughly 156,543.034 metres per pixel at the equator. At zoom z, resolution is156,543.034 / 2^z metres per pixel.
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
What is EPSG:3857?
EPSG:3857 is the Spherical Web Mercator projection — the projected coordinate reference system used by virtually every web tile map service (Google Maps, OpenStreetMap, Bing Maps, Mapbox, Esri basemaps). It encodes positions as X and Y values in metres, measured from the origin at the intersection of the equator and the prime meridian. The full valid range is roughly −20,037,508 m to +20,037,508 m on both axes, covering latitudes from about −85.05° to +85.05°.
What is EPSG:4326?
EPSG:4326 is the WGS 84 geographic coordinate reference system — the one used by GPS receivers, GeoJSON files, and most data exchange. Coordinates are stored as longitude and latitude in decimal degrees, with longitude from −180° to +180° and latitude from −90° to +90°. EPSG:4326 is the default for raw GPS data; EPSG:3857 is the default for web map tiles.
What is the difference between EPSG:3857 and EPSG:4326?
EPSG:3857 (Web Mercator) is a projected CRS — flat X/Y coordinates in metres. EPSG:4326 (WGS 84) is a geographic CRS — longitude and latitude in degrees on the ellipsoid. They both describe positions on Earth, but one is "flat" map-paper coordinates and the other is "round" globe coordinates. Web tile maps use 3857 for rendering; data is stored and exchanged in 4326. Converting between them is the most common projection task in modern GIS.
How do I convert EPSG:3857 to EPSG:4326?
Paste your EPSG:3857 X and Y values into the "Web Mercator → WGS84" tab on this page. You will get longitude and latitude in degrees back. The tool uses the standard EPSG:3857 ↔ EPSG:4326 transformation — the same math used by PROJ, GDAL, QGIS, ArcGIS, and PostGIS. All conversion runs in your browser; nothing is uploaded.
How do I convert EPSG:4326 to EPSG:3857?
Paste your longitude and latitude into the "WGS84 → Web Mercator" tab on this page. You will get X and Y in metres back, suitable for use with web tile services, Mapbox, MapLibre, Leaflet (when not using the default lat/lng API), or any system expecting EPSG:3857 inputs.
Why do Web Mercator coordinates look so large?
EPSG:3857 X and Y values 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. Any X/Y pair where the absolute value is in the millions is almost certainly EPSG:3857.
When should I use EPSG:3857 vs EPSG:4326?
Use EPSG:4326 (WGS 84 longitude/latitude) for data storage, data exchange, GeoJSON, GPS records, databases, and any calculation that needs geographic accuracy across large areas. Use EPSG:3857 (Web Mercator) when rendering tiles in Leaflet, Mapbox, MapLibre, OpenLayers, or working with map-event pixel/coordinate output.
Does EPSG:3857 distort distances and areas?
Yes — Web Mercator preserves angles (it is 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 EPSG:3857 coordinates for area or distance measurements; reproject to an equal-area CRS first.
What is the valid coordinate range for EPSG:3857?
EPSG:3857 covers longitudes from −180° to +180° (X from approximately −20,037,508 m to +20,037,508 m) and latitudes from approximately −85.05° to +85.05° (Y from approximately −20,037,508 m to +20,037,508 m). Polar regions beyond ±85.05° latitude cannot be represented in Web Mercator at all.
EPSG:3857 vs EPSG:4326
Web Mercator (EPSG:3857) and WGS84 (EPSG:4326) are the two coordinate systems you will encounter most often in GIS and web mapping. WGS84 uses latitude and longitude in decimal degrees — the familiar format used by GPS devices, Google Maps URLs, and most geospatial datasets. Web Mercator uses X and Y values in metres, projected onto a flat surface using the Mercator projection.
Web Mercator is the projection used by Google Maps, OpenStreetMap, Bing Maps, Mapbox, and virtually every web tile service. When you work in ArcGIS, QGIS, or other desktop GIS software and export coordinates from a web map layer, you will often get EPSG:3857 X/Y values rather than latitude/longitude. This tool converts between the two instantly.
Which software outputs Web Mercator coordinates?
Web Mercator coordinates appear when working with tile services or web map layers in ArcGIS, QGIS, Mapbox GL JS, Leaflet, and MapLibre. If you copy a feature location from a web map layer and the X value is in the millions (e.g. 1,500,000) rather than a number between −180 and 180, you are looking at EPSG:3857 coordinates.
Web Mercator (EPSG:3857) coordinates appear in tile map APIs, map click events, and some CAD exports — converting to WGS 84 decimal degrees is required before the data can be used in standard GIS workflows or stored in a spatial database.