MGRS Coordinate Converter
Convert latitude / longitude to a Military Grid Reference (and back).
Overview
The MGRS Coordinate Converter translates between latitude/longitude and the Military Grid Reference System used by NATO forces, search-and-rescue agencies, and many GIS systems. Enter a coordinate and the tool returns the MGRS string at the precision you choose; paste in an MGRS string and the tool returns the centre coordinate and bounding box of the cell.
MGRS is a friendly wrapper around UTM and UPS. Instead of long easting/northing numbers, MGRS packages them into a short alphanumeric code such as 33UXP04001736. The leading characters identify the grid square; the trailing digits give a position inside that square at a precision determined by their length. Two characters per axis (4 digits total) means 10 km accuracy. Five per axis (10 digits) means 1 m accuracy. This makes MGRS the standard way to call in coordinates over voice radio without garbling.
How it works
The first two or three characters identify the UTM grid zone designator - a zone number from 1 to 60 plus a latitude band letter from C to X (omitting I and O to avoid confusion with 1 and 0). The next two letters identify a 100,000 m square inside that zone using the AA-ZV grid. The remaining digits split evenly between easting and northing within that square. The polar regions (above 84°N or below 80°S) use UPS instead of UTM, with grid zone designators starting with A, B, Y or Z.
To convert lat/lng to MGRS, the tool first projects to UTM (or UPS at the poles), then computes the 100,000 m square letter pair from the zone-specific lookup table, and finally truncates the easting and northing to the requested precision. Decoding runs the steps in reverse and returns the south-west corner plus the cell centre.
Examples
- (48.8584, 2.2945) - the Eiffel Tower - encodes to
31UDQ4825411938at 10-digit precision (1 m). - (38.8977, -77.0365) - the White House - encodes to
18SUJ2335906776. 33UXP04001736decodes to roughly (48.16, 16.39) - Vienna.- (90, 0) - the North Pole - encodes to
ZAH0000000000using UPS (the polar grid).
FAQ
What is the relationship between MGRS and UTM?
MGRS is built on top of UTM (and UPS for polar regions). Every MGRS coordinate corresponds to a UTM easting/northing in a specific zone; MGRS just packages it into a more human-friendly string.
Why use MGRS instead of lat/lng?
MGRS strings are short, alphanumeric, and unambiguous over voice radio. Reading "1-8-S-U-J-2-3-3-5-9-0-6-7-7-6" is faster and less error-prone than reading two decimal-degree coordinates.
How precise is a 10-digit MGRS string?
The 10 digits split into 5 for easting and 5 for northing, giving 1 m precision. 8 digits give 10 m, 6 give 100 m, 4 give 1 km and 2 give 10 km.
Does the tool handle the polar regions?
Yes. Above 84°N and below 80°S the tool switches to the UPS-based MGRS encoding, with grid zone designators A, B, Y and Z.