Find a grid reference
The Ordnance Survey provide a splendid resource OpenSpace which allows you to read a grid reference directly from the pointer on a map.

1 - Use the zoom controls on the LH side of the map to change resolution, and drag with the mouse to the required location.

2 - Use the mouse to move the pointer to the required position.

3 - Without changing the pointer position, record the top two lines of coordinates at top right.

The grid reference is shown as 6 digits for each of easting and northing.  To convert to the format we require for database records is simple.  Here is a worked example, or use the form below valid only for Highland Region locations to do the hard work.

EAST: 237510   NORTH: 870834

The 100km square is given by the first digit in each coordinate, so 28.  To convert to letters, the 100km squares in Highland are 19 is NB; 29 is NC; 39 is ND; 18 is NG; 28 is NH; 38 is NJ; 17 is NM; 18 is NN.  The remaining digits follow, easting then northing ('along the corridor and up the stairs').

The converted OSGR is NH37 (10km); NH3770 (1km); NH375708 (100m); NH37517083 (10m); NH3751070834 (1m precision).
EAST coordinates: NORTH coordinates:

Resolution Grid reference
100km square (not acceptable for formal records)  
100m (usual preferred resolution)  
10m (should be used only for static organisms)  
1m (should be used only for static organisms)  
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