Maidenhead Grid Square Tool
Convert latitude/longitude to a ham radio grid square locator, or decode a locator back to coordinates.
Coordinates → Locator
Locator → Coordinates
What Is a Grid Square Locator?
A grid square locator (commonly the Maidenhead Locator System) is a compact way to describe a position on Earth. Instead of writing long latitude and longitude values, radio operators can exchange short codes like FN30AS to identify a location quickly and consistently.
The system is widely used in amateur radio contests, VHF/UHF contacts, satellite operations, propagation logging, and mapping tools. It works globally and is easy to share in voice, text, and digital modes.
How This Grid Square Locator Calculator Works
Coordinates to Locator
When you enter latitude and longitude, the calculator divides the world into progressively smaller cells:
- Field (letters): very large regions
- Square (digits): smaller sections inside the field
- Subsquare (letters): finer precision
- Extended levels: optional additional precision
You can choose locator length from 4 to 10 characters. Longer locators provide tighter positional accuracy.
Locator to Coordinates
If you already have a locator, this tool decodes it and returns:
- Approximate center latitude/longitude of that grid cell
- Cell bounds (south/north and west/east limits)
- Approximate grid cell size in degrees
Common Use Cases
- Sharing your location in a standardized ham-friendly format
- Submitting accurate contest logs
- Planning portable operations and field activations
- Checking if a contact was truly in a new grid
- Integrating location format into scripts, forms, or dashboards
Tips for Best Accuracy
1) Use Decimal Degrees
Enter coordinates in decimal format (for example, 34.0522, -118.2437) to avoid conversion errors.
2) Mind the Sign of Longitude
West longitudes are negative, East longitudes are positive. A wrong sign can place you thousands of miles away.
3) Choose Appropriate Precision
For casual operation, 6 characters are usually enough. For narrow-beam, microwave, or highly detailed work, use 8 or 10 characters.
Example Conversion
Suppose your position is latitude 51.5074 and longitude -0.1278. Enter those values and calculate a 6-character locator to get a practical operating grid for central London.
If another station sends a locator to you, paste it into the decode box to estimate their grid center and compare with maps or logging software.
Final Thoughts
A good grid square locator calculator saves time and reduces mistakes when exchanging location data. Whether you are contesting, chasing grid multipliers, or building a station toolkit, a fast lat/lon ↔ locator workflow is essential.
Bookmark this page and use it whenever you need quick Maidenhead conversions.