Template:OSGB n

Documentation
Converts an Ordnance Survey of Great Britain pair of grid letters to a northing value, measured in 100km units. This will be a single digit on mainland Britain. It may be 10, 11, or 12 for the Orkneys or further north.

Example:   gives 1. This value should be prepended to the second half of the grid reference digits (right-padded with zeroes to 5 digits). So TQ234678 has a northing of 167800.