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🧭 Coordinate Converters

MGRS Converter

Convert between lat/lng and MGRS references used by military and search-and-rescue teams.

This page explains how the mgrs converter works, the data and formulas behind it, and how to interpret the result. Coordinate conversions are exact to machine precision; the only source of error is the precision of the input. All formats describe the same location - the notation just differs. The tool is one of 329 free, open tools on JoseFitani for maps and geography. It runs in your browser with no sign-up needed. Use the search field or click the map to drop a pin - the tool uses standard mathematical formulas for each format, all based on the WGS84 datum (EPSG:4326) and returns the result in seconds. Below you'll find a step-by-step guide, real use cases, the methodology, FAQs, and data sources.

MGRS
31UDQ 48252 11955
Military Grid Reference System, 1 m precision
Plus Code
8FW4V75V+9R
Decimal Degrees
48.858400°, 2.294500°
Degrees Minutes Seconds
48° 51' 30.24" N, 2° 17' 40.2" E
UTM
31N 448252E 5411955.03N

MGRS is derived from the WGS84 ellipsoid series used on this site (accurate to a few metres) — suitable for reference and education, not for survey-grade work. Plus Codes follow the Open Location Code specification.

How to use this tool

1
Enter your input

Type your query, paste coordinates, or click on the map. The tool uses standard mathematical formulas for each format, all based on the WGS84 datum (EPSG:4326) to process your input locally in the browser.

2
View the result

The result appears instantly with the map showing your location. You can adjust by clicking elsewhere or searching a new place.

3
Copy or share

Click Copy to save to clipboard, or Share to send a direct link with the exact inputs.

What people use this tool for

Relaying positions by radio

Search-and-rescue teams communicating by voice radio need positions that are short, unambiguous, and hard to mishear. An MGRS grid reference reads cleanly over a crackly channel, with none of the decimal points and long digit strings that cause errors in lat/lng readbacks.

Example: A rescue volunteer in Colorado radios a grid like 13S DB 12345 67890 to the command post, giving the team a 10-metre square without pronouncing a single decimal point.
Sharing an emergency location

Backcountry travellers in trouble need to give rescuers a position that pinpoints them precisely and works with the maps the rescue team carries. An MGRS reference from a GPS unit drops straight onto military and topographic map grids that responders already use.

Example: A backcountry skier in British Columbia texts the MGRS grid from her GPS to dispatchers, letting the helicopter crew plot the exact square before takeoff.
Recording archaeological sites

Archaeologists publish site locations as grid references that other researchers must be able to relocate decades later. MGRS gives a compact, standardised reference that matches the grid printed on the survey maps used across the project area.

Example: An archaeologist in Jordan logs each trench in MGRS to match the grid references used in the project's published site gazetteer.
Teaching land navigation

Navigation instructors teaching map and compass skills use MGRS because it connects the GPS in a student's hand to the grid printed on military training maps. Converting between lat/lng and MGRS builds the habit of cross-checking electronic and paper navigation.

Example: An instructor in Wales has students convert their GPS lat/lng readings into MGRS and then find the same squares on their issued training maps.

How it's calculated

MGRS extends UTM with a 100 km grid square identifier and numeric easting/northing.

The calculation runs in your browser - no data is sent to our servers. Map tiles come from OpenStreetMap (ODbL license), geocoding uses Nominatim (1 request/second limit), and elevation uses the Open-Elevation API backed by SRTM data. All are free, open services.

All calculations use the WGS84 datum (EPSG:4326), the same as GPS. For other datums (NAD27, NAD83, ETRS89), a separate conversion is needed. The difference is typically under 1 metre - negligible for most uses but important for survey-grade work.

The formulas match those in professional GIS software (QGIS, ArcGIS, Global Mapper), just in a browser-friendly form. For sub-metre accuracy, use professional software with ellipsoidal calculations. Results are shown in multiple units: km and miles for distance, km²/m²/hectares/acres for area, metres and feet for elevation. Conversion factors are exact (1 mile = 1.609344 km), so the only error source is input precision.

Related tools and resources

For more tools in this category, explore the related tools listed below. Each tool includes full documentation, examples and FAQs. Explore related tools in our Coordinates category for complementary functionality. See the Tools index for all 329 tools, or read our blog for in-depth articles on geography and maps.

Frequently asked questions

What precision does MGRS provide?

From 100 km down to 1 meter depending on the number of digits used.

What is MGRS?

The Military Grid Reference System extends UTM with a two-letter identifier for each 100 km grid square, producing references like 33U UB 12345 67890. The letters replace the raw zone easting/northing with something humans can read, say, and write without error. The trailing digits give easting and northing within the square.

How precise is an MGRS grid reference?

Precision is set by the number of digits: 4 digits locate a 1 km square, 6 digits a 100 m square, 8 digits a 10 m square, and 10 digits a 1 m square. Each added digit pair narrows the position tenfold. Emergency and field work typically uses 8 digits, which is precise enough to find a person while staying short enough to radio.

What do the letters in an MGRS reference mean?

The first group, such as 33U, is the UTM zone number plus the latitude band letter. The second pair, such as UB, identifies the specific 100 km square within that zone. The numbers that follow are the easting and northing measured from the square's southwest corner.

Why do the 100 km grid letters repeat in different places?

The letter pairs cycle every few zones by design, so the same two letters label squares in several parts of the world. The full reference stays unique because the zone-and-band prefix disambiguates them. Always quote the complete reference, prefix included, when sharing a position.

Does MGRS cover the polar regions?

No. Like UTM, MGRS is not defined near the poles; it stops at 84 degrees north and 80 degrees south. Beyond those latitudes the Universal Polar Stereographic (UPS) system takes over. If your work is in the high Arctic or Antarctica, you need UPS grids instead.

Does the MGRS converter work offline?

Yes. The conversion between lat/lng and MGRS is pure mathematics executed entirely in your browser. No server, lookup, or connection is involved, so it works in the field far from any signal.

Should I use MGRS or UTM?

They describe the same projection, so choose by audience. MGRS is the compact, human-readable form suited to radio, print, and fieldwork with others. UTM's raw easting/northing numbers suit computation in GIS and spreadsheets. Convert freely between them as the situation demands.

Why does my GPS show a different grid reference?

First check the datum: most GPS units default to WGS84, but some maps and older units use local datums that shift the grid by tens or hundreds of metres. Also confirm the precision setting, since a 6-digit and an 8-digit reference for the same point legitimately look different.

Data sources & methodology