Additional geographic information
Mapping and navigational fields
Our grid references locate the centroid of a postcode in units of 1m.
Grid references are included for the most of the UK, with the exception of postcodes that belong to PO Boxes.
The Channel Islands (postcode areas JE and GY) and the Isle of Man (postcode area IM) are available as an option, these having been calculated by Allies at postcode district level on the same basis as the UK mainland grid. Note that northings for the Channel Islands are negative numbers.
The Northern Ireland (postcode area BT) grid does not have the same origin as the one used for the rest of the United Kingdom. An approximate conversion of Northern Ireland grid references to the same origin as the rest of the UK is obtained by adding 13000 to the northing and subtracting 17000 from the easting of the NI references. This should not be regarded as an exact conversion.
The UK grid runs out in the far north of Scotland, where a letter is used for the first digit of the grid northing in order to retain a 6 character reference. However, for ease of use we supply a 7 digit numeric grid reference which can be used directly with other UK grid references.
Our OSGB36 coordinates are expressed in degrees for the 1m grid reference for a postcode; 15 digits: sign, 3 digits, decimal point, 10 decimal places.
These latitude & longitude values are given on the Airey 1830 ellipsoid and reference the OSGB36 datum. The values correspond to those on current OS Maps for Great Britain. Northern Ireland values are computed using the Irish Transverse Mercator projection.
Longitude east of Greenwich is a positive decimal value. Longitude west of Greenwich is a negative decimal value.
Our ETRS89 coordinates are expressed in degrees for the 1m grid reference for a postcode; 15 digits: sign, 3 digits, decimal point, 10 decimal places.
These latitude and longitude values are given on the WGS84 ellipsoid and reference the ETRS89 datum. The values correspond to those used in global positioning systems in Great Britain and Europe. Note that many online map providers such as Google Maps use GPS maps and hence the ETRS89 latitude and longitude coordinates should be used with these providers.
Longitude east of Greenwich is a positive decimal value. Longitude west of Greenwich is a negative decimal value.Get A Free Quote