Key takeaways
- Read from the recipient and premises down toward the Post Town and postcode
- A property may use a name instead of a street number
- Post Town is a postal element and should not be replaced with a guessed city
- County is often optional, while the postcode should retain its internal space
Authorship and review
Read our editorial and review principles- Written by
- Random Address Generator Editorial Team
- Reviewed by
- International Address Format Review Team
- Latest substantive update
- Published a plain-English guide to reading and writing UK premises, locality, Post Town, county, and postcode lines.
Read the address from the delivery point outward
The top lines identify the recipient and premises: a flat, building, house name, number, or street. A dependent locality may follow. The Post Town appears near the bottom, with the postcode usually on the final domestic line.
Do not search for a US-style city-state-ZIP pattern. The UK does not use a mandatory state field, and the familiar town name in conversation may not be the postal Post Town.
What each UK address line is doing
The premises lines narrow the destination inside a building or property. The thoroughfare line identifies the street. Locality lines help distinguish places before the Post Town. The postcode routes the address to a compact delivery area and belongs in its own field in software.
Some addresses are shorter; others need a building name and several locality lines. A fixed assumption that every UK address has a house number, street, city, county, and postcode will reject valid shapes.
| Example line | Role | Form field |
|---|---|---|
| Flat 4, Ash Court | Sub-building and building | Address Line 1 |
| 18 King Street | Number and thoroughfare | Address Line 2 |
| Upper Wapping | Dependent locality | Address Line 3 or locality |
| Bristol | Post Town | Town / City |
| BS1 4DJ | Postcode | Postcode |
Post Town is not a decorative city label
The Post Town is part of the postal address. It can differ from the administrative area or the place name a person uses locally. Preserve the value returned by Royal Mail or supplied with the authoritative address rather than substituting a better-known nearby city.
In a form, the familiar Town / City label can collect the Post Town, but the data model should document what the field means. Calling it City and later treating it as an administrative city creates avoidable reporting errors.
Postcode matters more than a required county field
Write the postcode in uppercase with one space before the final three characters. Save it as text. A format rule can normalize spacing and case, but only a current Royal Mail lookup can confirm the assigned address.
County is not universally required in modern UK postal addresses. A form that forces it often collects guesses, repeats, or historical county names. Keep it optional unless the application has a separate, explained business need.
- Accept lowercase input and normalize for display
- Restore one internal postcode space
- Do not treat a regex match as a delivery match
- Allow County to remain blank
- Keep Post Town and county in separate fields
How to write a British address without losing a line
Copy the recipient and premises lines in their supplied order, then the thoroughfare and any locality, followed by the Post Town and postcode. Add UNITED KINGDOM as the final line when posting from abroad. Do not add the country line to domestic UK mail.
For software tests, include a house name with no number, a flat plus building, a blank county, a lowercase postcode that normalizes to uppercase, and a Post Town that differs from the user's familiar locality.
Frequently asked questions
How do you read a UK address?
Start with the recipient and premises, then read through the street and locality to the Post Town and postcode at the bottom.
What is a Post Town?
It is a postal routing element used in the UK address. It may not match the administrative city or the place name someone uses in everyday speech.
Does a UK address need a county?
Not always. Many current postal addresses work without a county, so forms should not make it universally required.
How should a UK postcode be written?
Use uppercase letters and keep one space before the final three characters, such as BS1 4DJ.