What does an MGRS string look like?

An example is 30U XC 99319 10158. The 30U is the grid zone designator, XC is the 100 km square identifier, and the two five-digit numbers are the easting and northing within that square at 1 metre precision.

How are the 100 km square letters chosen?

The column letter cycles through three alphabets of eight letters keyed to the zone number, and the row letter cycles through a 20-letter sequence keyed to whether the zone is odd or even. Together they uniquely identify a 100 km square within the zone.

What precision levels does MGRS support?

MGRS supports 10 km, 1 km, 100 m, 10 m and 1 m precision by using 1 to 5 digits for each of easting and northing. This tool outputs 1 metre precision with five digits each.

Why does MGRS leave out the I and O letters?

The letters I and O are skipped throughout MGRS because they are easily confused with the digits 1 and 0 when read or transmitted by voice.

Lat/Lng to MGRS Converter

This tool converts WGS-84 latitude and longitude into an MGRS string — the Military Grid Reference System used by NATO forces, search-and-rescue teams and many GIS tools. MGRS is a more compact, human-friendly encoding of the same grid that UTM uses.

How it works

The point is first projected to UTM to get a zone, easting and northing. MGRS then encodes that position in three parts:

30U XC 99319 10158
└┬┘ └┬┘ └──┬──┘ └──┬──┘
 GZD  sq   easting  northing

The grid zone designator (GZD) is the UTM zone number plus a latitude band letter. The 100 km square is two letters: a column letter derived from the easting and zone, and a row letter derived from the northing and whether the zone is odd or even. The remaining easting and northing within that square are written as five digits each for 1 metre precision. The letters I and O are skipped everywhere to avoid confusion with 1 and 0.

Tips and notes

MGRS covers the same latitude range as UTM, roughly 80°S to 84°N. Shorter strings simply drop trailing digits to give coarser precision — 10 km, 1 km, 100 m or 10 m. Everything runs locally in your browser. To decode an MGRS string back to coordinates, use the MGRS to Lat/Lng converter.