How to read an MGRS grid
An MGRS grid like 18T VR 44545 30011 looks cryptic, but it’s only four parts read in order. Once you know the rule “right, then up”, you can read any grid in seconds.
- The four parts of a grid
- Read right, then up
- 4, 6, 8 or 10 digits
- Shortening a grid
- Common mistakes
- Practise on a live map
The four parts of a grid
- Grid zone (18T): the world is cut into 60 zones, each 6° of longitude wide, numbered 1 to 60 from west to east. A letter adds an 8° band of latitude. Ottawa and Montréal are in zone 18, Québec City in zone 19, and Alberta in zones 11 and 12.
- 100 km square (VR): each zone is split into squares 100 km on a side, each named by two letters.
- Easting (44545): how far right (east) you are inside that square, in metres.
- Northing (30011): how far up (north) you are inside that square, in metres.
When everyone works in the same area, people often drop the zone and square and just give the numbers, e.g. “grid 445 304”.
Read right, then up
The easting always comes first. Find the vertical grid line to the left of your point and read right, then the horizontal line below it and read up. The classic memory aid is “in the door, then up the stairs”.
4, 6, 8 or 10 digits
A grid always has an even number of digits: split them in half, first half easting, second half northing. More digits means a smaller square.
| Digits | Example | Precision | Typical use |
|---|---|---|---|
| 4 | 44 30 | 1 km | A general area |
| 6 | 445 300 | 100 m | Standard map reading on a 1:50,000 map |
| 8 | 4454 3001 | 10 m | A building, a bridge, a trail junction |
| 10 | 44545 30011 | 1 m | GPS-grade positions |
Shortening a grid
To go from 10 to 8 or 6 digits, cut the end of each half: don’t round. 44545 30011 becomes 4454 3001 (8 digits) and 445 300 (6 digits). Cutting keeps you in the square that contains the point, which is how MGRS is designed to be read.
Common mistakes
- Swapping the halves: reading up first. Always right, then up.
- Uneven digits:
4454 301is not a valid grid. Both halves need the same length. - Rounding instead of cutting when shortening a grid.
- Dropping the zone and square near a boundary: the same numbers exist in every 100 km square, so give the full grid when you’re near an edge or talking to someone far away.
Practise on a live map
MGRS Cardinal shows the grid under the crosshair as you move the map. Turn on the grid lines to see the 1 km squares with their numbers, then check your reading against the grid box at the bottom. You can also check any grid with the MGRS converter.
Frequently asked questions
Why does MGRS use letters?
The two letters replace the long first digits of a UTM coordinate, so grids are shorter to say and write.
Do I always need the zone and the square letters?
Only when someone could be confused. Within one area people use just the numbers. Near a square boundary, or with people far away, give the full grid.
Is MGRS the same as a map’s “grid reference”?
Canadian and NATO topographic maps are printed with the same UTM grid, so a 6-digit grid read from a paper map matches the numbers in MGRS Cardinal. Check the grid zone and square printed in the map’s margin.
Try it now
Open the map, turn on the grid lines, and read the grid under the crosshair. Free, no account needed.
Open MGRS Cardinal MGRS converter