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Home > Guides > Addressing a letter to the UK
Address a UK letter with the recipient name first, then house number and street, then town or city, then the postcode on its own last line, adding UNITED KINGDOM when posting from abroad. Leave the county out unless the address needs it, and print the postcode in capitals so Royal Mail sorting machines read it cleanly.
One honest limit first: LetterAgent only mails to recipients with US or Canadian addresses, so it cannot send this letter to the UK for you. The addressing rules below still apply when you post the letter yourself from a post office or a mailbox abroad.
UK addresses run from the specific to the general, much like US addresses, but with two differences that trip people up. The postcode sits on its own last line, and the county is usually skipped. Royal Mail sorting relies heavily on the postcode, so getting that line right matters more than getting the county right. A typical address looks like this:
| Line | What goes there | Example |
|---|---|---|
| 1 | Recipient name | Ms J. Patel |
| 2 | House number and street, or house name | 14 High Street |
| 3 | Town or city | Oxford |
| 4 | Postcode, in capitals | OX1 4AA |
| 5 (from abroad) | Country name, in capitals | UNITED KINGDOM |
Some UK homes have a house name instead of a number, such as Rose Cottage, and some have both a flat number and a building name. Put the flat first, then the building, then the street. If the address you were given includes a county, you can keep it between the town and the postcode, but Royal Mail does not need it for delivery when the postcode is correct.
A UK postcode has two parts separated by a space: an outward part that points to a postal town or district, and an inward part that narrows it to a street or a small group of addresses. The outward part mixes letters and numbers, and the inward part is always one number followed by two letters. That space in the middle is part of the format, not decoration, so keep it. Postcodes in the UK are far more precise than US ZIP codes: one postcode often covers only one side of one street, which is why a correct postcode can carry a letter even when a house number is smudged.
Write the postcode in capitals and double-check the characters that people commonly confuse: the letter O against the number zero, and the letter I against the number one. Postcodes never use the letters C, I, M, O, Q, V, or X in certain positions by design, but you do not need to memorize the rule. Just copy the postcode exactly as the recipient gave it to you, and check it against a second source if the letter matters.
Three mistakes show up again and again. First, Americans write the state-style line and add a county they found on a map, which adds clutter but rarely causes a delay. Second, they put the postcode on the same line as the town, which sorting machines handle less cleanly. Third, they write England, Scotland, Wales, or Northern Ireland as the country line instead of UNITED KINGDOM. Those names are fine inside a UK address, but for international mail the country line should read UNITED KINGDOM, since that is the name postal systems worldwide file the UK under.
Return addresses work the other way around. When you post from the US, your return address goes in the top left corner of the envelope in US format, with your ZIP code and USA on the last line. That way, if the letter cannot be delivered, Royal Mail can hand it back through the international system instead of holding it.
No special envelope is required, and the old blue par avion sticker is no longer needed: international sorting now reads the country line and the postage, not a sticker. Use a plain envelope, write clearly or print the address, and leave the bottom right area of the envelope clear, since that is where sorting marks and barcodes go. A printed label beats handwriting for any address with an unfamiliar postcode, because a machine reads print more reliably than even neat handwriting.
If the letter is valuable or time-sensitive, ask at the post office about tracking and proof of delivery for international mail. Standard international postage covers delivery, not a signature, and a lost letter abroad is harder to trace than a domestic one, so keep a copy of anything you cannot easily replace.
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