# UK Address Format: Line Order, Post Town and Postcode > A UK address runs from the most specific element to the least: name, building or flat, house number and street, locality if needed, post town in capitals, then the postcode alone on the last line. The county is optional. When mailing from abroad, add UNITED KINGDOM as a final line below the postcode. - URL: https://address-valid.com/address-formats/uk-address-format/ - Language: en - Updated: 2026-10-19 - Publisher: AddressValid (OnlineBuilders LLC, https://onlinebuilders.biz) Royal Mail's Postcode Address File held 32,429,019 delivery points in its August 2026 release, spread over 1,810,763 postcodes and 1,500 post towns. That works out to fewer than 18 addresses per postcode on average. The postcode alone already narrows a letter down to a handful of doors, which is why British mail forgives a lot of small mistakes above it and almost none in the postcode itself. The format below follows Royal Mail's entry in the [UPU address catalogue](https://www.upu.int/UPU/media/upu/PostalEntitiesFiles/addressingUnit/gbrEn.pdf), the document postal operators use to explain their rules to each other. ## The line order Royal Mail expects British addresses are built from small to large. Each element gets its own line, left-aligned, without commas or full stops at the line ends. **UK address lines, top to bottom** 1. **Addressee** Person or organisation, e.g. `Ms A Patel` or `Leda Engineering Ltd`. 2. **Building** Flat, building name or sub-building, only if it exists: `Flat 4` or `Victoria House`. 3. **Number and street** `27 Harbour Road`. A dependent street (a smaller road off a main one) goes on the line above the main street. 4. **Locality** Village or district, only where Royal Mail lists one: `Weybourne`. 5. **POST TOWN** In capital letters: `HOLT`, `BRISTOL`, `LONDON`. 6. **Postcode** Alone, capitals, one space: `NR25 7HG`. Source: Royal Mail entry in the UPU address catalogue Most domestic addresses need only four of these lines. Here is a typical house in a town: ``` Ms A Patel 27 Harbour Road BRISTOL BS1 6XY ``` The street and postcode in that example are invented to show the shape. Every element of a real address should come from what the recipient gives you or from a lookup against Royal Mail data. ## Post town, locality, county The post town is the delivery office town that Royal Mail assigns, not necessarily the place where the recipient thinks they live. Someone in a suburb of Bristol may have BRISTOL as their post town even though their council tax goes to another authority. If a lookup returns a post town you did not expect, trust the lookup. Localities are the dependent and double dependent localities in Royal Mail's data: village names that are needed because two streets with the same name exist under one post town. The UPU sheet shows the pattern with a rural address: `1A Seastone Cottages`, `Station Road`, `Weybourne`, `HOLT`, `NR25 7HG`. Drop the locality and the postman in Holt may still find it. Not always, though. Drop it in a post town with two Station Roads and the item gets delayed. Counties are the part people argue about. The UPU entry is explicit: the county name is no longer required when the post town and postcode are given. My advice: leave it out of printed labels and keep it, if you must, as a separate field in your database for reporting. Historic counties, postal counties and administrative ones do not always match, so a county field invites conflicts without helping delivery. ## The six UK postcode patterns Every UK postcode has an outward code (area plus district) and an inward code (sector plus unit). The inward code is always one digit followed by two letters. The outward code comes in six shapes, where A is a letter and N is a digit: | Pattern | Example | Typical use | |---|---|---| | AN NAA | M2 5BQ | Single-letter areas such as Manchester | | ANN NAA | M34 4AB | Two-digit districts in single-letter areas | | AAN NAA | CR0 2YR | Most two-letter areas | | AANN NAA | DN16 9AA | Two-letter areas with two-digit districts | | ANA NAA | W1A 4ZZ | Central London districts | | AANA NAA | EC1A 1HQ | Central London districts | The examples come straight from Royal Mail's UPU entry. The single exception to these patterns is GIR 0AA, a legacy code originally used by Girobank. So a UK postcode is between five and seven characters plus the space. If your form field caps postcodes at seven characters including the space, `EC1A 1HQ` will not fit. That bug is common. Our article on [postcode validation with regular expressions](https://address-valid.com/validation/postcode-regex/) has a pattern that accepts all six shapes and explains why the government's published regex lets some garbage through. ## Flats, building names and business addresses Flats are where most UK addresses go wrong in online forms. Royal Mail data stores a flat as a sub-building, and you will see it written two ways: ``` Flat 4 27 Harbour Road ``` or, on one line, `Flat 4, 27 Harbour Road` in a form that only offers one street field. On the envelope, the two-line version is cleaner. If your checkout has an "Address line 2", that is where the flat or building name belongs; [our guide to address line 2](https://address-valid.com/address-formats/address-line-2/) covers what else people put there and what to do about it. Named buildings without a number stay on the line above the street or, in rural areas, replace the street entirely. The UPU sheet lists `The Manor`, `Norwood Hill`, `HORLEY`, `RH6 0HP` as a complete address. No number at all, and it is still valid. Business mail adds the organisation name, and optionally a department, between the person and the building. Large organisations sometimes have their own postcode, in which case the street matters less than the postcode and the organisation name. ## Sending to the UK from another country From abroad, the postcode moves from the last line to the second-to-last. The country goes underneath in capitals: ``` Ms A Patel 27 Harbour Road BRISTOL BS1 6XY UNITED KINGDOM ``` Write UNITED KINGDOM rather than UK, GB or England. Canada Post's addressing guidelines, for instance, list "UK" as an example of what not to write, and Deutsche Post asks for the destination country spelled out in capitals as well. Do not put a country prefix like "GB-" in front of the postcode either. Deutsche Post, for one, rules out country codes in front of the postcode on mail abroad. Country lines and languages are covered in [how to address international mail](https://address-valid.com/address-formats/international-address-format/). **Same address, domestic versus from abroad** | | Posted in the UK | Posted from abroad | |---|---|---| | Postcode position | Last line | Second-to-last line | | Country line | no | UNITED KINGDOM | | County | Optional | Optional | | Post town in capitals | yes | yes | | Punctuation at line ends | no | no | ## What a format check can and cannot tell you Format checks catch the mechanical errors: a postcode with the letter O where a zero belongs, a missing space, the town typed into the postcode field, a missing house number. Our [address format checker](https://address-valid.com/address-checker/) does exactly that for the UK and fourteen other countries, in your browser, and prints the block in the order shown above. What it cannot tell you is whether 27 Harbour Road actually sits inside BS1 6XY. That needs a match against Royal Mail's PAF, which is licensed data, updated continually; the [Powered by PAF statistics page](https://www.poweredbypaf.com/the-august-2026-statistics-for-the-postcode-address-file-paf-are-now-available/) reported an increase of 17,902 delivery points in the August 2026 release alone. If you hold thousands of UK customer records, a one-off PAF cleanse followed by lookup at the point of entry will fix more than any amount of manual formatting. Teams that want this built into their own pipeline can talk to a data studio such as [OnlineBuilders](https://onlinebuilders.biz/solutions/data-analytics). For a single letter, the next step is simpler: type the address into the checker, compare the output with the six lines above, and copy the result onto the envelope. ## FAQ ### Do I need to include the county in a UK address? No. Royal Mail's own entry in the UPU address catalogue says the county is no longer required if the post town and postcode are present. Adding it does no harm, but it does not speed up sorting and it can make a long address spill onto an extra line. ### Can the postcode go on the same line as the town? Royal Mail's guidance is that the postcode stands alone on its own line, in capitals, without punctuation. Many web forms and labels squeeze it onto the town line and the item still arrives, but the clean format is the town on one line and the postcode on the next. ### Is the space in a UK postcode required? Yes. The last three characters, the inward code, are always separated from the outward code by a single space, as in SW1A 2AA. Software that stores postcodes without the space should add it back before printing. ### Where does the flat number go? On its own line above the street, for example Flat 4 followed by 27 Harbour Road. If a form only has one street field, Flat 4, 27 Harbour Road works too. Pick one form and keep it consistent across your systems. Photo: Geographer, CC BY-SA 2.0 (https://commons.wikimedia.org/wiki/File:Hillside_Avenue_Postbox_%5E_Royal_Mail_Dump_Box_-_geograph.org.uk_-_3853669.jpg)