What is a Maidenhead grid square?

It is a compact way of naming a location, used in amateur radio for logging and contests. Alternating letter and digit pairs divide the world into progressively smaller cells, so four characters name a square about 111 by 156 km and six characters narrow it to a few kilometres.

How do I find my grid square?

Enter your latitude and longitude here and read the locator. Six characters is the standard for logging; four is used for contest multipliers and beacon reports.

How large is a six-character grid square?

2.5 minutes of latitude by 5 minutes of longitude — about 4.6 km north to south, and 9.3 km east to west at the equator, narrowing as you move toward the poles.

Why does the longitude pair cover twice as many degrees?

Longitude runs the full 360° around the globe while latitude spans only 180° from pole to pole. Doubling the longitude step keeps the two pairs in step so the same number of characters covers the whole world.

What is the beam heading between two grid squares?

It is the initial great-circle bearing from your square's centre to the other, which is where a directional antenna should point. The return path is not simply the opposite number, because a great circle changes bearing along its length.

Maidenhead Grid Square Converter

Convert coordinates to a Maidenhead locator and back, with the square's bounds, the distance to another grid and your beam heading.

The Maidenhead Grid Square Converter runs entirely in your browser. Your coordinates are never uploaded.

Open the Distance Between Coordinates tool

About Maidenhead Grid Square Converter

A Maidenhead locator compresses a position into a handful of characters that are easy to read over the air and easy to log. Alternating letter and digit pairs subdivide the globe: two letters give a field 20° by 10°, two digits narrow it to a square, and each further pair shrinks the cell again — six characters put you inside a few kilometres, ten inside a few metres. Longitude always comes first, and every level is twice as coarse east-west as north-south, because longitude wraps 360° while latitude spans only 180°. This converter goes both ways, shows the exact bounds of the square you land in, and works out the great-circle distance and beam heading to any other locator.

Features

Coordinates to a locator at 4, 6, 8 or 10 characters
Locator back to a centre point with the full bounding box
Cell size in degrees at every precision
Great-circle distance in kilometres and miles between two squares
Beam heading and the return heading, with a compass point
Correct case handling: field upper, subsquare lower
GeoJSON polygon of the square for dropping onto a map
Everything converts on your device

How to use the Maidenhead Grid Square Converter

Choose whether you are starting from coordinates or a locator
Enter the latitude and longitude, or the grid square
Pick the precision you need — six characters is the norm on air
Add a second square to get the distance and beam heading

Example

Input

41.714, -72.727 at six characters

Output

FN31pr — centre 41.7292, -72.7083 · cell 0.0417° × 0.0833°

F is the field, 3 the square, p the subsquare — longitude first at every level.

Common errors & troubleshooting

The locator decodes to somewhere far from the expected place. — Longitude comes first in Maidenhead, unlike a latitude/longitude pair. Swapping the two puts you in the wrong hemisphere entirely, which is the single most common mistake.
A logging program rejects the locator's case. — The convention is upper case for the field, digits, then lower case for the subsquare — IO91wm. Some software is strict about it, so the converter normalises the case for you.
Two stations in the same square report slightly different distances. — Distance is measured between square centres, and a six-character square is a few kilometres across. For contest scoring that is the accepted method; for anything precise, use eight or ten characters.

Frequently asked questions

What is a Maidenhead grid square?: It is a compact way of naming a location, used in amateur radio for logging and contests. Alternating letter and digit pairs divide the world into progressively smaller cells, so four characters name a square about 111 by 156 km and six characters narrow it to a few kilometres.
How do I find my grid square?: Enter your latitude and longitude here and read the locator. Six characters is the standard for logging; four is used for contest multipliers and beacon reports.
How large is a six-character grid square?: 2.5 minutes of latitude by 5 minutes of longitude — about 4.6 km north to south, and 9.3 km east to west at the equator, narrowing as you move toward the poles.
Why does the longitude pair cover twice as many degrees?: Longitude runs the full 360° around the globe while latitude spans only 180° from pole to pole. Doubling the longitude step keeps the two pairs in step so the same number of characters covers the whole world.
What is the beam heading between two grid squares?: It is the initial great-circle bearing from your square's centre to the other, which is where a directional antenna should point. The return path is not simply the opposite number, because a great circle changes bearing along its length.

Related tools

Coordinate Converter (DMS & Decimal) — Convert coordinates between decimal degrees, DMS and degrees-decimal-minutes, both ways, in your browser.
Distance Between Coordinates — Measure the great-circle distance between two latitude/longitude points in km, miles and nautical miles, with bearing and a map.
Geographic Midpoint Calculator — Find the true midpoint of two or more coordinates, with optional weights.
Plus Codes Converter — Convert between latitude/longitude and a Plus Code (Open Location Code) both ways, with the covered bounding box and cell size.
MGRS Converter — Convert between latitude/longitude and MGRS (Military Grid Reference System) coordinates, both ways, in your browser.
Geohash Converter — Encode latitude/longitude to a geohash and decode a geohash back to coordinates, with bounding box and neighbors.