Short answer
A worldwide projection system that divides Earth into 60 6°-wide longitude zones, each projected as a transverse Mercator centred on its meridian. Distances and areas inside one zone are easy linear-metric computations; the projection is valid 80°S to 84°N latitude.
Detailed explanation
UTM divides the world into 60 longitude zones, each 6° wide, numbered 1–60 starting from longitude 180°W. Within each zone, coordinates are projected from the WGS84 ellipsoid onto a flat plane using a transverse Mercator projection — true-shape (conformal) within the zone, with scale factor 0.9996 at the central meridian to spread distortion across the zone width.
Coordinates inside a zone are given as (easting, northing) in metres. Easting is measured from a false 500,000 m origin at the central meridian (so values are always positive within the zone). Northing is from the equator: 0 at the equator going north, with a false 10,000,000 m offset for the southern hemisphere (so values are also always positive there).
UTM coordinates are great for distances and areas within a zone — straightforward metric arithmetic with sub-cm error over typical survey areas. Across zone boundaries (every 6° of longitude) the math breaks; long east-west features need to be projected into a common zone or kept in geographic coordinates.
Latitude coverage is 80°S to 84°N. Polar caps use UPS (Universal Polar Stereographic) — not implemented in this site's Coordinate Converter, but the L-band cluster is covered.
Try it interactively
Coordinate Converter
Open the toolRelated terms
MGRS
A compact alphanumeric grid coordinate system built on top of UTM, used by NATO, US DoD, aviation, and search-and-rescue. A typical MGRS reference like 33TUM1234567890 encodes a position to 1 m precision in 15 characters — survives voice transmission and SMS reliably.
WGS84
The reference ellipsoid and datum used by GPS and the de-facto GNSS standard. Semi-major axis a = 6378137 m, flattening f = 1/298.257223563. Position differences from local datums (NAD83, ETRS89, GDA2020, CGCS2000) range from tens of cm to several metres depending on region.
ECEF
A 3-D Cartesian coordinate system with origin at Earth's centre of mass, X axis through the prime meridian / equator, Z axis along Earth's rotation axis. The native frame in which GNSS receivers compute satellite and user positions before projecting to lat/lon.