UK Postcodes

06th October 2014

Hierarchical nature of postcode geography


SW 15 1 QP
Area District Sector Unit
Postcode Area SW 124
Postcode District SW15 2,987
Postcode Sector SW15 1 11,185
Unit Postcode SWS15 1QP 1,744,539
Delivery points residential 27,909,529


Average number of delivery points per postcode is 18, mode is 14 and number of delivery points range from 1 to 100.


  • 1856 – London was divided into 10 Postal Districts by Sir Rowland Hill who reformed and made postal services more efficient.
  • Postal districts were denoted by letters such as N-northing, E-easting, etc.
  • 1917-postal sub-districts introduced by adding numbers after postal districts.
  • Today original postal district refers to Postcode Area and sub-districts to modern Postcode District.
  • 1959-Decision was made to use Postcodes that contain both numeric and alphabetic characters. The first postcodes were introduced on a trial basis in Norwich.
  • 1974- The whole of UK had been allocated to Postcodes.


  • Postcodes are used for efficient mail delivery in terms of the costs and speed.

Usage and Application

Postcodes and its spatial reference (coordinates) found application in almost all parts of UK’’s business and public life. Appending various auxiliary data to unit postcodes and postcode sectors provides great source of information for market analysis, public sector planning and small area economic planning.

  • Location based analysis – each postcode have been allocated coordinates
  • Linking Postal and Census geography
  • Data visualisation – mapping
  • Customer profiling
  • Market and Opinion Research
  • Geodemographics
  • Marketing and Advertising /Direct Marketing
  • Utilities
  • Retail
  • Media
  • Local Authorities
  • Health Authorities
  • Police
  • Catchment area analysis
  • Financial services – banks, insurance companies