Maidenhead Locator Converter

The Maidenhead grid divides the globe into 18×18 fields (letters A–R, each 20°×10°), then 10×10 squares (0–9, each 2°×1°), then 24×24 sub-squares (a–x, each 5'×2.5'). A 6-character locator like FN31pr identifies a rectangle roughly 5 km × 4 km. Prefixes and rounding follow the IARU convention adopted at the 1980 VHF conference in Maidenhead, UK.

1. Enter latitude/longitude in decimal degrees to compute the grid.
2. Or paste a 4- or 6-character locator to get the center coordinates.
3. Use 6-character precision for QSO logging; 4 characters for propagation reporting.