# How to Calculate the Boundaries of an UTM Zone

Calculating the eastern and western boundaries of a UTM is very straightforward.  Developed by the U.S. Army, the Universal Transverse Mercator (UTM) is an international plane (rectangular) coordinate system. In the coordinate system, the world is divided into 60 zones of 6 degrees longitude. Each zone extends 3 degrees east and west from its central meridian and are numbered consecutively west to east from the 180-degree meridian. Transverse Mercator projections may then be applied to each zone.

Difficulty Level: Easy    Time Required: 1 minute

Here’s How:

• UTM zones are all 6 degrees wide and increase from west to east starting at the -180 degree mark.
• Calculate the eastern boundary of any UTM zone by multiplying the zone number by 6 and substract 180.
• Subtract 6 degrees to obtain the western boundary.
• Therefore to find the eastern boundary of UTM zone 11: Eastern boundary of zone 11 = (11 * 6) – 180 = -114 degrees.
• Western boundary of zone 11 = -114 – 6 = -120 degrees.