Web Mercator to Lat Long
Convert Web Mercator (EPSG:3857) X/Y metres to latitude/longitude (EPSG:4326) — and back — instantly, shown on a map. Free, runs in your browser.
Web Mercator (EPSG:3857) → Lat/Long
Lat/Long → Web Mercator (EPSG:3857)
Working with tile coordinates, a PostGIS geometry, or a GeoJSON that came out in metres like -8236028, 4976712? That's Web Mercator (EPSG:3857) — paste the X/Y to get normal lat/long, or go the other way. It's the projection every web map uses under the hood, so this is the conversion you hit constantly in GIS and mapping code. Runs entirely in your browser.
Web Mercator vs Lat/Long
Web Mercator (EPSG:3857) is the projection behind almost every online map — Google Maps, OpenStreetMap, Mapbox, Leaflet and MapLibre all render in it. Coordinates are metres on a flat square spanning about ±20,037,508 m. Plain latitude/longitude (EPSG:4326) is degrees on the WGS84 globe. You display 3857 but usually store and query 4326 — so converting between them is an everyday task in mapping work.
The formula
Because it's a conformal (shape-preserving) projection, Web Mercator keeps angles right but stretches area badly near the poles — which is why it clips at ±85.0511°.
Frequently Asked Questions
How do I convert Web Mercator to latitude and longitude?
Enter the X and Y values in metres (EPSG:3857). The converter applies the inverse spherical Mercator projection and returns WGS84 latitude and longitude in decimal degrees. It also works the other way — enter lat/long to get X/Y metres.
What is Web Mercator (EPSG:3857)?
Web Mercator is the projection used by virtually every web map — Google Maps, OpenStreetMap, Mapbox, Leaflet and MapLibre. Its coordinates are in metres on a square that spans roughly ±20,037,508 m in both X and Y. Its EPSG codes are 3857 (and the older 900913 / 102100).
What is the difference between EPSG:3857 and EPSG:4326?
EPSG:4326 is plain latitude/longitude in degrees on the WGS84 datum. EPSG:3857 (Web Mercator) is those coordinates projected onto a flat map in metres. Web maps display 3857 but usually accept 4326 for input — this tool converts between the two.
Why does Web Mercator stop at 85 degrees?
To keep the map square, Web Mercator clips latitude at about ±85.0511°. At that latitude the Y value reaches the same ±20,037,508 m extent as X, so the poles are never shown.
Is Web Mercator accurate for distances?
No — it preserves shape and direction but badly distorts area and distance toward the poles (Greenland looks as big as Africa). Use it for display and tiling; for real-world distance, convert to lat/long and use a great-circle calculation.