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FieldGrid

How to convert lat long to MGRS and MGRS to lat long on your phone

In FieldGrid, go to Waypoints, tap +, switch the selector at the top of the sheet from Position to Manual, and type the coordinate as decimal "lat, lon": the MGRS grid shows up under the field as you type, no save needed yet. Going the other way, type the MGRS grid, save it, flip Primary to Lat / Lon, and copy the waypoint.

3 min read · Updated 2026-09-23

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Two systems that don't speak to each other

Phones, text messages and most mapping apps talk latitude and longitude. Military maps, land nav courses and a lot of search-and-rescue teams talk MGRS. Someone texts you "37.74870, -119.58720" and your map only has a grid printed on it, so you need the conversion, or the reverse.

A browser converter does the job until you're somewhere without signal, which on a land nav course happens more often than not. FieldGrid runs the same maths on the phone itself, offline, because that's the whole point of having it.

Convert lat long to MGRS

  1. Open the Waypoints tab and tap +.
  2. In the sheet that opens, switch the selector at the top from Position to Manual.
  3. In Coordinate, type the decimal latitude and longitude separated by a comma, for example 37.74870, -119.58720. The hint under the field reads Supported: MGRS, Lat/Lon (comma-separated decimals).
  4. Read the live preview under the field: → 11SKB 7205 8108.
  5. If you want to keep the point, give it a Name and a Category and tap Save.

Convert MGRS to lat long

  1. In Waypoints, tap +, switch the selector at the top of the sheet from Position to Manual, and type the grid in Coordinate, for example 11SKB 7205 8108. Spaces are optional, and any even number of digits from 2 to 10 works.
  2. Tap Save.
  3. Open the gear, then Settings > Coordinate format, and set Primary to Lat / Lon.
  4. Back in Waypoints, press and hold the waypoint's row to copy its coordinate: 37.74865°, -119.58729°.

If you only want to look at the place, GOTO on the map takes the same grid and centres the map there, without saving anything.

One point, three ways

FieldGrid results for one point
You typeFieldGrid givesNote
37.74870, -119.5872011SKB 7205 81088-digit grid, 10 m square
11SKB 7205 810837.74865°, -119.58729°South-west corner of that 10 m square
37.74870, -119.5872011N 272058 4181085Same point in UTM

Why the round trip doesn't land you back on the same spot

An 8-digit grid names a square, 10 m on a side, not a point. Convert lat/long to MGRS and you keep only the square; convert back and you get that square's south-west corner. In the example above, the corner sits about 10 m from where you started. That's the grid's resolution talking, not a bug in the maths.

Hand it a 10-digit grid instead and FieldGrid still reads it, drops the point inside a 1 m square, then shows it back to you as 8 digits anyway.

What it flatly won't convert

  • Degrees, minutes and seconds, like 37°44'55" N. Convert that to decimal degrees yourself first.
  • UTM typed in by hand. FieldGrid will show you UTM for your own position, but it doesn't accept UTM as input.
  • Batches of points, one at a time only. No pasting in a list.

Each saved conversion eats a waypoint slot. Free gives you 5, plus one more for every short rewarded ad you choose to sit through; Pro takes the cap off.

Questions and answers

Is MGRS the same as UTM?
They share the same zones and metres, but MGRS replaces the long easting and northing with a 100 km square letter pair and fewer digits. FieldGrid shows both for the same point.
Can I convert without saving a waypoint?
Yes for lat/long to MGRS: the preview appears before you save, so you can just read it and cancel. For MGRS to lat/long you need to save the point to copy it in the other format.
Does it work offline?
Yes. The conversion is done on the phone; only the map background needs data.
Why is there a ° after each number?
That is how FieldGrid writes decimal degrees, to 5 places (about 1 m). Remove the symbols if another app needs plain numbers.

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