County Maps US

Tools Coordinates

UTM to Lat/Long Converter

Both directions in one form. The conversion runs the full Transverse Mercator series, not an approximation, so survey-grade inputs stay survey-grade.

How to use it

  1. UTM to lat/long: enter the zone (1 to 60), pick the hemisphere or type the latitude band letter, then the easting and northing in metres. Press Convert.
  2. Lat/long to UTM: type the latitude and longitude (any format) in the lower form and press Convert.
  3. Either way the point is pinned on the map and the result rows can be copied. Drag the pin to convert a new point.

How it works

The projection is the Transverse Mercator on the WGS84 ellipsoid using the Krüger series to third order (the same method as GeographicLib and PROJ), scale factor 0.9996, false easting 500,000 m and false northing 10,000,000 m in the southern hemisphere. The error against the exact projection is well under a millimetre within a zone.

UTM is defined between 80 degrees south and 84 degrees north; polar regions use UPS, which this tool does not compute. The Norway and Svalbard zone exceptions are applied when converting from latitude and longitude. A coordinate given in a neighbouring zone (eastings far from 500,000) still converts, with a note that the zone is not the standard one for that point.

Questions

What is the difference between a band letter and a hemisphere?
Both say which half of the globe the northing counts from. Band letters C to M are south, N to X are north (there is no I or O). The form accepts either; a band letter also sets the hemisphere.
Why is my easting six digits and northing seven?
Eastings run from about 160,000 to 840,000 m across a zone; northings run from 0 at the equator to about 9,300,000 m at 84 degrees north, or from 10,000,000 m at the equator downward in the south.
Which datum is assumed?
WGS84. UTM coordinates on NAD83 are the same to within a metre or two in North America; those on NAD27 differ by up to about 200 m and need a datum shift this tool does not apply.

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