British vs American English Spelling: 12 Common Differences

Colour or color? Theatre or theater? Learn the most common spelling differences and the simple patterns behind them.

There are many spelling differences between British and American English. Often the word sounds the same and only the spelling changes. But sometimes the pronunciation is different too. The good news is that many differences follow simple patterns, so once you know the pattern, you can spell lots of words correctly.

1. Words ending in -our (British) and -or (American)

Many British words end in -our, while the American version ends in -or.

Colour / Color

What's your favourite colour? Mine is blue.

Neighbour / Neighbor

If you want to get on well with your neighbours, keep the noise down at night and say hello when you see them. A loud party until 4am on a weeknight is a quick way to upset them!

Rumour / Rumor

Rumours spread very quickly, especially online. Don't believe everything you hear, because the rumour might not be true.

Humour / Humor

Have you got a good sense of humour? If you can understand jokes in another language, it's a great sign that your English is improving. Just don't be surprised if some British humour seems a bit strange!

Odour / Odor

A dog's sense of smell is much better than a human's. Dogs can notice an odour that is far too weak for us to smell, which is why police use them at airports.

Favourite / Favorite

One of Britain's favourite dishes is chicken tikka masala. Notice that the extra "u" can also appear in the middle of a word.

2. Words ending in -re (British) and -er (American)

Theatre / Theater

Going to the theatre is a popular thing to do in London, and the most famous theatres are in the West End. In the USA, the most famous theatres are on Broadway in New York.

3. Words ending in -ise (British) and -ize (American)

Apologise / Apologize

British people love to apologise, even when it isn't their fault! If someone bumps into you in the street in Britain, don't be surprised if you hear "sorry".

Note: you will sometimes see -ize in British English too, but -ise is more common in the UK.

4. Words ending in -mme (British) and -m (American)

Programme / Program

It's annoying when you're watching a TV programme and there are lots of adverts. That's one reason many people now watch recorded programmes or streaming services.

Note: for computers, British English also uses "program".

5. Other common differences

Aeroplane / Airplane

London Heathrow is the busiest airport in the UK, with over 80 million passengers a year. That's a lot of aeroplanes, or "planes" for short!

Cheque / Check

Few people write cheques now because of cards and online banking. Many UK shops no longer accept them.

Pyjamas / Pajamas

Some people call them PJs or even "jim-jams". Whatever you call them, don't forget to change out of your pyjamas before you go to the shops!

Aluminium / Aluminum

Do you wrap your baked potatoes in aluminium foil? This one is special: the British word has an extra "i" and an extra syllable, so it sounds different too.

Quick summary

• -our / -or: colour, neighbour, humour, favourite
• -re / -er: theatre, centre, metre
• -ise / -ize: apologise, organise, realise
• -mme / -m: programme
• Different words: aeroplane, cheque, pyjamas, aluminium

More British vs American English

Learn the differences in everyday words, from trousers and pants to sweets and candy, in our British vs American English words quiz.

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