EPSG codes and coordinate reference systems

There are 164 UTM zone definitions in the converter and they are not listed individually here, because the code is predictable. On WGS 84 the northern zones are EPSG:326 followed by the two-digit zone number, and the southern zones are EPSG:327 followed by it. Zone 43 north is EPSG:32643; zone 43 south is EPSG:32743.

The zone number itself is floor((longitude + 180) / 6) + 1, so each zone is a 6-degree strip of longitude. On the central meridian the scale is held one part in 2500 short, which is 40 cm per kilometre; toward the edge of the strip it climbs back through unity and reaches about one part in 1000 near the equator.

The UTM zone finder applies that to a real place: click the map, type coordinates or use your location, and it returns the zone, the EPSG code, the central meridian and the MGRS grid square.

Every conversion runs in your browser with proj4. Nothing is uploaded, there is no size limit and there is no sign-up, which is the whole reason the tool exists.

The cost of that is grid-based datum transformations. NTv2 and NADCON grid files are large binaries that proj4 cannot load client-side, so a definition referencing one has that reference stripped rather than failing silently. Expect metre-level agreement on datum changes such as NAD83 to WGS 84, not centimetre-level. For survey-grade work use National Geodetic Survey tooling or a desktop GIS with the grids installed.

The about page lists the method behind every tool on this site, including this limitation.