GARS (Global Area Reference System) is a standardized way to name areas on the Earth. It divides the world into 30-minute cells identified by a longitude band number and two latitude letters, like 380MK. Each cell splits into four 15-minute quadrants and each quadrant into nine 5-minute keypads, so 380MK17 names an area about 9 km across. It was developed as a common area reference for coordinating between air and ground operations.

How do you read a GARS reference like 380MK17?

Read it left to right, coarse to fine. 380 is the longitude band (counted eastward from 180 degrees West in 30-minute steps). MK is the latitude band (counted northward from 90 degrees South, skipping the letters I and O). The optional 1 picks the quadrant (1 NW, 2 NE, 3 SW, 4 SE) and the optional 7 picks the 5-minute keypad, numbered 1 to 9 like a phone pad starting at the northwest corner.

What is the difference between GARS and MGRS?

GARS names areas; MGRS names points. A full GARS reference is a rectangle about 9 km across, built from simple 30-minute slices of latitude and longitude. MGRS is a metric grid built on UTM zones that can pinpoint a single square meter. GARS is used to deconflict and assign areas quickly (especially in air-ground coordination); MGRS is used to locate things precisely on the ground.

How precise is a GARS cell?

A 30-minute cell is about 55 km tall and up to 55 km wide (narrower at high latitudes). A 15-minute quadrant is about 28 km, and a 5-minute keypad about 9 km. GARS deliberately stops there; it is an area reference, not a targeting system.

Guide

What Is GARS and How It Differs from MGRS

July 13, 2026

GARS, the Global Area Reference System, names areas with short codes like 380MK. The world is sliced into 30-minute cells; each cell splits into four 15-minute quadrants and each quadrant into nine 5-minute keypads, so 380MK17 pins down a rectangle about 9 km across. It exists so that pilots, ground teams, and planners can all say the same thing about the same patch of the map in seven characters or fewer.

That is the fundamental contrast with MGRS: an MGRS reference names a point (down to a single meter), while a GARS reference names a box. If you have ever coordinated a search sector, deconflicted airspace, or assigned an area to a team, you were doing the job GARS was designed for.

The anatomy of a GARS reference

A full reference has four parts, coarse to fine. Take 380MK17, a keypad in the Swiss Alps:

380

Longitude band: 001 to 720, eastward from 180°W in 30′ steps

Latitude band: AA to QZ, northward from 90°S (no I or O)

Quadrant: 15′ quarter (1 NW, 2 NE, 3 SW, 4 SE)

Keypad: 5′ ninth, numbered like a phone pad from NW

Stop at any point: 380MK is a cell, 380MK1 a quadrant, 380MK17 a keypad.

The numbering is fixed and worldwide. Band 001 starts at 180°W and the numbers count eastward, two per degree, up to 720. The letters start at AA on the Antarctic edge and climb to QZ near the North Pole, skipping I and O so nothing reads as a 1 or 0 over a radio.

How a cell subdivides (try it)

The easiest way to internalize quadrants and keypads is to click through one cell. This is 380MK, the 30-minute cell over the Alps used in the screenshots below:

380MK17

380MK17 is a 5-minute keypad, roughly 9 km per side.

center 46.7917, 9.5417 · 5′ cell

Try it: quadrants are numbered 1 to 4 (NW, NE, SW, SE), keypads 1 to 9 like a phone pad starting at the northwest corner.

What GARS looks like on a map

Zoomed out, the grid is the plain 30-minute lattice; every cell carries its five character name:

MapGridder showing the GARS grid over the Alps with 30-minute cells labeled 378ML through 388MG, each cell carrying its five character reference — 30-minute GARS cells across the Alps. One code per cell, no zones, no exceptions.

Zoom in and the grid keeps up: cells split into quadrants (381MK1), then into keypads (381MK47), the reference simply growing a digit at each step:

MapGridder zoomed into the Livigno area with the GARS grid at the 5-minute keypad level, cells labeled 381MK37 through 381MK49 — The same grid at the 5-minute keypad level. Each rectangle is roughly 9 km across.

GARS vs MGRS

Both systems are worldwide, both compress a location into one string, and both come from the same defense world. They answer different questions: GARS answers “which box?”, MGRS answers “which spot?”

	GARS	MGRS
Names	An area (cell, quadrant, keypad)	A point (down to 1 m)
Built on	Plain latitude/longitude slices	UTM zones and metric squares
Finest unit	5′ keypad, about 9 km	1 m square
Example	380MK17	32TMT 6540 4715
Cell shape	Angular rectangles (narrow near poles)	True metric squares (within a zone)
Typical job	Assigning and deconflicting areas, air-ground coordination	Reporting and finding exact positions

The structural difference matters in practice. MGRS inherits UTM’s 6° zones, so two points on opposite sides of a zone boundary get references that look unrelated, and grid squares get clipped at the seams. GARS has no zones at all: the same simple rule covers the planet, which is why it works well as a shared bookkeeping grid. The price is precision; a GARS keypad is a 9 km box, useless for pointing at a building. The two systems are complements, not competitors: brief the area in GARS, report the position in MGRS.

See both grids on a live map

The fastest way to build intuition is to flip between the two grids over terrain you know. Open the map, pick GARS or MGRS in the Grid panel, and watch how each one divides the same mountains. Searching for a reference like 380MK17 flies straight to that cell.

Open the GARS grid on a live map

Have coordinates to convert? The lat/long to GARS converter gives you the cell, quadrant, and keypad in one shot. For the point-precision side of the story, read how to read a military grid reference.