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.

Worked example

Royal Observatory, Greenwich sits at approximately 51.4778° N, -0.0014° E. Converting to MGRS yields:

30U XC 99319 10158

Breaking it down:

• 30U — UTM zone 30, latitude band U (56–64° N range)
• XC — 100 km square identifier within zone 30U
• 99319 — easting within the 100 km square, in metres (1 m precision)
• 10158 — northing within the 100 km square, in metres (1 m precision)

Precision levels

MGRS expresses precision by the number of digits in the easting/northing pair:

To truncate to coarser precision, simply drop trailing digits from each numeric block — always the same number from easting and northing.

MGRS vs UTM vs DMS

MGRS is essentially UTM made compact for human transmission — the zone and 100 km square letters replace the large UTM easting/northing numbers with a short alphanumeric code that is easier to read aloud and less prone to transposition error. Letters I and O are excluded everywhere to prevent confusion with digits 1 and 0. Everything runs locally in your browser. To decode an MGRS string back to coordinates, use the MGRS to Lat/Lng converter.