Latitude/longitude ↔ UTM converter
Convert GPS coordinates between latitude/longitude and UTM (WGS84 / NAD83) in your browser, with notes on zones, datums and accuracy for field work.
Type a position and convert – nothing leaves your browser.
Using the numbers in the field
UTM (Universal Transverse Mercator) splits the world into 60 north–south zones, each six degrees of longitude wide. Inside a zone, a position is an easting and a northing in metres, which makes it easy to measure distances on a paper map with a ruler. Most of the eastern United States falls in zones 16, 17 and 18; the Rockies sit in zones 12 and 13.
The converter uses the WGS84 ellipsoid. NAD83, the datum on most modern U.S. maps, differs from WGS84 by about a metre or two – far less than a typical phone GPS error – so for hiking, stream surveys and photo locations the two can be treated as the same. Older maps drawn on NAD27 can be off by tens of metres or more, so check the datum printed in a map’s margin before you compare coordinates.
More on reading maps, layers and public data viewers is in our Maps & Data guide.