The postcode is a part of a coding system created by the Royal Mail. The postcodes are an abbreviated form of addresses and enable a set of delivery points to be grouped.


In a postcode, the first two letters (SW) refer to the nearest large town or city - the postcode area - and there are 124 of these in Britain. The number which follows (1A) is a district within that area. There are 3,000 postcode districts in the UK. In the second half of the postcode, the first number (1) tells the sorting office which sector the letter should go to - there are 9,000 sectors. And the last two letters (AA) represent your individual unit - on average about 17 homes.

Did you know?

  • The Queen has a unique postcode for Buckingham Palace, SW1A 1AA.
  • Even Father Christmas has his own postcode so he can receive all those sacks of Christmas lists. It is SAN TA1 (in Canada it’s HOH OHO ...) and letters sent to this postcode actually do arrive.
  • The postcode HD7 5UZ in Huddersfield, West Yorks, covers seven streets, more than any other in the UK.
  • In 2008 footballer Steven Gerrard built a new gym in his back garden. It was so big it had a different postcode to his house.
  • Britain is one of seven post coding systems in the world that use an alphanumeric system - a combination of letters and numbers - which allows a greater number of unique combinations to be used.
  • The combination of letters and numbers was also chosen because people can remember a mixture of numbers and letters more easily than a list of numbers.
  • Countries without postcodes include Jamaica, Ghana, and Hong Kong.
  • Ireland didn't have a postcode system until it gave every address a unique, seven-character postcode called Eircode in 2015.