# How to Calculate the Boundaries of an UTM Zone

Caitlin Dempsey

Updated:

Calculating the eastern and western boundaries of a UTM is very straightforward.

## What is the Universal Transverse Mercator (UTM) Map Coordinate System?

Adopted by the U.S. Army in 1947, the Universal Transverse Mercator (UTM) is an international plane (rectangular) coordinate system for the map projection, Transverse Mercator, on which it is based.

In this coordinate system, the world is divided into 60 zones of 6 degrees longitude. UTM zones are numbered from 1 to 60, with the first zone being 180 degrees longitude with each subsequent zone increasing eastward.

Each zone extends 3 degrees east and west from its central meridian and are numbered consecutively west to east from the 180-degree meridian.

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Transverse Mercator projections may then be applied to each zone.

The Northern and Southern Hemispheres are separated by the Universal Transverse Mercator (UTM) convention. The northern hemisphere’s UTM zone is designated as UTM North, which is represented by a positive value. The UTM zone has a negative value in the Southern Hemisphere, and is therefore known as UTM South.

## Units for the Universal Transverse Mercator (UTM) Coordinate System

The distance in each zone is measured in meters. Distance in meters to the east are known as the easting and distance in meters to the north are known as the northing.

## Calculating the Boundaries of a UTM 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 subtracting 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.

## References

The Universal Transverse Mercator (UTM) Grid. (n.d.). U.S. Geological Survey Publications Warehouse. https://pubs.usgs.gov/fs/2001/0077/report.pdf

This post was originally published August 25, 2006 and has since been updated.