Convert projected coordinates in metres (Web Mercator or UTM easting/northing) back to decimal degrees latitude and longitude. Enter the X and Y, tell the tool which projection they are in, and read the WGS84 result, free and in your browser.
You cannot turn raw metres into degrees on their own. A value like 448265 is a distance east of some projection's origin, and it means a completely different place in Web Mercator than in a UTM zone. So the first step is always to know the source coordinate system. If the data came from a web map or a tile service, it is almost certainly Web Mercator (EPSG:3857). If it came from a survey, a national grid or engineering plans, it is more likely a UTM zone recorded in the file's metadata or its .prj sidecar.
Web Mercator coordinates X = 255989, Y = 6250779 reproject to about 48.858, 2.300 in decimal degrees (latitude, longitude), a point in Paris. Web Mercator values grow non-linearly with latitude, which is why the northing is far larger than the longitude suggests.
UTM zone 31N coordinates E = 448265, N = 5411932 reproject to roughly 48.858, 2.295 (latitude, longitude). Note the zone (31) and hemisphere (N) are essential: the same easting and northing in zone 32 or in the southern hemisphere would land somewhere entirely different.
| System | EPSG | Where you meet it |
|---|---|---|
| Web Mercator | 3857 | Google Maps, OpenStreetMap, Mapbox, web tiles |
| UTM (WGS84) | 326xx (N) / 327xx (S) | Surveying, engineering, drone and military data |
| WGS84 lat/long | 4326 | The degrees you are converting to, not metres |
Not without knowing the projection. Metres are eastings and northings in a projected coordinate system, so you must say which one, Web Mercator (EPSG:3857) or a specific UTM zone, before they can be turned back into longitude and latitude degrees.
Web Mercator values are usually large and can be negative (for example X = -8,238,310). UTM eastings sit between roughly 160,000 and 834,000 and northings are 0 to 10,000,000, always positive, with a separate zone number. If a file came from a web map or tile scheme it is almost always Web Mercator (EPSG:3857).
The easting is the X value (metres east of the projection origin) and the northing is the Y value (metres north). Enter X in the first box and Y in the second. Swapping them puts the point in the wrong place, the same trap as swapping latitude and longitude.
Use the zone the data was created in, it is usually recorded in the file's metadata or .prj. Each zone is six degrees of longitude wide. Also tick 'southern hemisphere' for data below the equator, because northings there are measured from a false origin.
No. The reprojection runs in your browser with proj4, the same library desktop GIS uses. Your coordinates never leave your device and it works offline once loaded.
