WGS 84 GPS and UTM Coordinate Converter

Converting between GPS and UTM

WGS 84 latitude and longitude are angular coordinates. UTM projects them into easting and northing in metres within a selected zone. The same numbers identify different positions in different zones, so the zone and hemisphere are essential parts of every record. Zone 31 has a central meridian at 3° east. At its intersection with the equator, easting is 500000 m and northing is zero.

Scope

The calculation uses a sixth order series on the WGS 84 ellipsoid. Forward conversion derives the hemisphere from latitude, while inverse conversion requires you to select it. Special extended zones must be chosen manually. The tool does not change the datum of a GPS record. Treating UTM data from another datum as WGS 84 gives the wrong position. Confirm the source datum, epoch, zone and any required transformation parameters before field use.

Check the inverse conversion on a known axis

For inverse conversion, choose zone 32, northern hemisphere, easting 500000 m and northing 0 m. The zone central meridian is 6 × 32 − 183 = 9°. Easting equals the defined central meridian offset and northing corresponds to the equator, so the result is latitude 0° and longitude 9°. This example checks a defined projection axis instead of relying on a memorized table value for a complicated intermediate point. Converting the same angular point forward should recover the original metre coordinates.

Enter easting (E) and northing (N) in their respective fields. When copying from another program, remember that its axis order may differ. Do not confuse a thousands separator with a decimal separator in metre coordinates. Latitude and longitude fields require decimal degrees. Do not enter degrees, minutes and seconds as though they formed one decimal number. Agreement between forward and inverse conversions checks internal consistency only. The same wrong zone or datum could have been used in both directions. Many displayed decimal places do not establish field accuracy. Measurement quality and numerical precision of the coordinate conversion are different matters.

Frequently asked questions

How do you calculate the UTM zone from longitude?

For example, longitude 3° falls in standard UTM zone 31. The zone number is the whole part of the distance east of the antimeridian divided by six degrees, plus one, and this preliminary check excludes regional zone exceptions and datum transformations, so the zone used for field data must still be verified against its source record.

Calculate with these values