List of postcode areas in the United Kingdom

[1] There are currently 121 geographic postcode areas in use in the UK and a further three often combined with these covering the Crown Dependencies of Guernsey, Jersey and Isle of Man.

[2] The single or pair of letters chosen for postcode areas are generally intended as a mnemonic for the places served.

[2] The Crown dependencies (which are not part of the United Kingdom) did not introduce postcodes until later, but use a similar coding scheme.

Some fall within the range 91 to 99 (e.g. S98 for payments to MNBA Ltd; NE98 for Department for Work and Pensions, Central Office, Newcastle-upon-Tyne).

However, there are many exceptions to this - e.g. American Express has the postcode area BN88; in Glasgow G58 1SB is allocated to National Savings, formerly National Savings Bank, as a mnemonic (SB, and with 58 looking like SB), though it is located in the G43 postcode district; and in Glasgow G70 is allocated to HMRC which is located in G67.

[7] The non-geographic postcode area BX has been introduced for addresses which do not include a locality; this allows large organisations long-term flexibility as to where they receive their mail.

This postcode area is used by Lloyds Banking Group (BX1 1LT), HSBC (BX8 0HB) and parts of HM Revenue and Customs like VAT (BX5 5AT) and Pay As You Earn (BX9 1AS).

The non-geographic postcode area XX is used by online retailers for returns by Royal Mail, and was used for COVID-19 test samples.

These are not UK postcodes, even though many are formatted in a similar fashion: Other overseas territories have introduced their own more extensive postcode systems: Civilian residential and business addresses in Akrotiri and Dhekelia are served by Cyprus Postal Services and use Cypriot postal codes.