GLOSSARY

MGRS: how the Military Grid Reference System works

MGRS, the Military Grid Reference System, is a way of writing a position as a short string of letters and digits instead of latitude and longitude. NATO armed forces use it for position reporting, and many search and rescue teams use it because it is quick to read out over a radio and easy to measure on a paper map.

Last checked 2026-10-23

How an MGRS coordinate is built

MGRS is built on the UTM projection (and UPS near the poles). A full coordinate has three parts, read from the largest area to the smallest:

Grid zone designator, such as 30U: a 6° wide UTM zone number plus a latitude band letter.
100 km square, such as XC: two letters naming one square inside that zone.
Easting and northing: an equal number of digits for each, measured inside the square.

More digits, smaller square

An MGRS reference names a square, not a point. With one digit each for easting and northing the square is 10 km wide; with five digits each it is 1 m. In practice, teams agree on a precision: 30U XC 9 1 narrows it to 10 km, 30U XC 993 102 to 100 m, and 30U XC 99303 10200 to 1 m. All three contain Nelson’s Column in Trafalgar Square, London. Inside one operation people often drop the zone and square and read out only the digits, because everyone already knows where they are.

A casualty position over the radio

A mountain rescue team member reports a casualty: “Grid 731 262, on the path below the ridge.” The coordinator plots it on the map and sends the nearest team. Read as latitude and longitude, the same position needs about twice as many characters and leaves room for a mix-up between degrees and minutes. That is one reason mountain rescue teams and military units favour grid references.

MGRS in Sinkaos

Your format, the same position

WGS 84, UTM, MGRS and others, each person seeing coordinates in the format they prefer.

Paste and go

Paste an MGRS reference into search, online or offline, and the map jumps there.

Works with military partners

Two-way Cursor on Target exchange with TAK apps and APP-6 symbols, so a grid reference means the same thing to both sides.

MGRS questions

Is MGRS the same as UTM?

They describe the same grid. UTM writes full metre values for easting and northing; MGRS replaces the leading digits with the two-letter 100 km square, which makes references shorter.

Is the US National Grid the same thing?

The US National Grid uses the same structure as MGRS on the WGS 84 datum, so references match in the United States.

Do civilian teams need MGRS?

Not always. It helps most when you work with the military or with teams that read grid references from paper maps. See civil-military cooperation.