EPSG / CRS Transformer
Reproject coordinates between WGS84, Web Mercator, every UTM zone, and other common national grids. Pure proj4 math in your browser — no upload, no sign-up, free.
Common EPSG codes
| Code | Name | Units |
|---|---|---|
| EPSG:4326 | WGS84 lat/long | degrees |
| EPSG:3857 | Web Mercator | metres |
| EPSG:32601–32660 | UTM zones 1–60 North | metres |
| EPSG:32701–32760 | UTM zones 1–60 South | metres |
| EPSG:27700 | British National Grid | metres |
To find the UTM zone for any longitude: zone = floor((lng + 180) / 6) + 1. New York at -74° is in zone 18; London at 0° is in zone 30; Tokyo at 140° is in zone 54.
Frequently Asked Questions
What coordinate reference systems does this transformer support?
WGS84 (EPSG:4326), Web Mercator (EPSG:3857), all 60 UTM zones (northern and southern hemispheres), British National Grid (EPSG:27700), Irish Grid (EPSG:29903), ETRS89, NAD83, and a curated set of US State Plane zones. Choose a source and target CRS, enter coordinates, and the transformer applies the projection math in your browser.
How accurate is the transformation?
The transformer uses proj4-style parameter strings (the same format QGIS, PostGIS, and the proj library use). Accuracy is typically sub-metre for the supported systems. For survey-grade work (millimetre) you would need time-dependent datum transformations (e.g. WGS84 → NAD83(2011) with an epoch), which require grid-shift files this tool does not bundle.
What is the difference between a datum and a projection?
A datum (WGS84, NAD83, ETRS89) defines the size and shape of the Earth and the origin of the coordinate system. A projection (UTM, Mercator, State Plane) is the math that flattens that sphere onto a 2D plane with X/Y metres. Every projected CRS combines a datum and a projection — e.g. "UTM zone 18N on WGS84".
Where can I find the EPSG code for my area?
Search epsg.io by country or city name. The EPSG registry is the authoritative source. Common ones: 4326 (WGS84 lat/lng), 3857 (Web Mercator), 27700 (UK National Grid), and the UTM zone for your longitude (zone = floor((lng+180)/6)+1).