?

The Complete List of
English Spelling Rules

Lesson 20: Differences between
British and U.S. English


In this series of lessons, you will learn useful spelling rules in English.

This final lesson will talk about some common differences between British and U.S. English spelling. Of course both forms are correct, but it is important for you to use one style of English consistently in your writing.

a boy writing on a typewriter

Download a free worksheet + answer key.

Several of the rules below talk about suffix spelling differences between British and U.S. English. There are also some rules you should remember about double consonants when adding endings to words.

Finally, there is a list of some common words that are spelled differently. These cannot be explained by a simple rule, so you should learn them separately. 

These are only the most common spelling differences that you will see frequently. You will find more examples as you encounter new words and read different kinds of texts.

1. -ise versus -ize and -yse versus -yze

a woman in a messy room

Cindy needs to organise / organize the play room.

Click Here for Step-by-Step Rules, Stories and Exercises to Practice All English Tenses

Click Here to get the English Short Stories Book and Workbook



In British English, the ending -ise for verbs is more common, though some words also end in -ize. In U.S. English, -ize is much more common, but you will also find some verbs that end in -ise.

This difference applies to words with Greek roots. But instead of looking up each new word's root, you should simply study this list of the most common words with a different spelling in British and U.S. English.

You will also see that some words are spelled -yse in British English, while they end in -yze in U.S. English.

British English U.S. English     
realise realize
recognise recognize
finalise finalize
analyse analyze
paralyse paralyze
catalyse catalyze

Also remember that when you add noun suffixes to these words, they will maintain their s or z, depending on the spelling rules you choose.

So, organise becomes organisation, but organize becomes organization. Realise becomes realisation while realize becomes realization.

2. -our versus -or

a man with a huge ice cream cone

Which flavour / flavor of ice cream is your favourite / favorite?

One of the most common differences between British and U.S. English spelling is the our / or variation.

Here are some common words with this spelling difference:

British English U.S. English      
colour color
behaviour behavior
labour labor
neighbour neighbor
harbour harbor
rumour rumor
honour honor

3. -re versus -er

a water faucet

You should drink between two and three litres / liters of water every day.

Although there are many words that end in -er in British English, you will not find the -re ending in U.S. English. Remember that this difference only applies to root words. So, the comparative -er ending is the same in both styles.

Here are the most common examples of this spelling difference:

British English U.S. English    
calibre caliber
centre center
theatre theater
sabre saber
metre meter
sombre somber

4. Doubling the final L in British English

a tourist getting on an airplane

James is travelling / traveling to Asia for the first time.

When we add endings to words that end in l (the verb endings -ed, -ing, -er, and -est, or the noun suffixes -er and -or), the word's final l is usually doubled in British English.

In U.S. English, the final consonant is usually only doubled when the stress is on the final syllable of the word and the words ends in a single consonant and a single vowel. Check the articles on adding -ed and adding -ing for more details.

Here are some of the most common words with this spelling difference:


British English U.S. English     
cancelling canceling
crueller crueler
signalled signaled
labelled labeled
modelling modeling
counsellor counselor
traveller traveler

5. Miscellaneous spelling differences

a tall office building

This is an elevent-storey / story building.

There are also some common words that are spelled differently in the two styles, but do not respond to a specific rule. Here are some of the most important ones you should study.

British English U.S. English  
aeroplane airplane
aluminium aluminum
cheque check
cosy cozy
furore furor
kerb curb
mould mold
moustache mustache
pyjamas pajamas
sceptical skeptical
speciality specialty
sulphur sulfur
tyre tire

Review

So, let's review what we have learned about the differences in spelling in British and U.S. English:
  1. The suffixes -ise and -yse are more common in British English, while -ize and -yze are more common in U.S. English.

  2. The ending -our is more common in British English, while -or is more common in U.S. English.

  3. The ending -re is more common in British English, while -re is more common in U.S. English.

  4. The final l is doubled in words in British English when certain word endings are added (-ing, -ed, -er, -est, and -or), while the final l is only doubled when the stress is on the final syllable and the root word ends in a single consonant and a single vowel in U.S. English.

  5. There are also some common words that have a different spelling in British and U.S. English but do not follow specific rules. 


Download a free worksheet



Get Vocabulary, Grammar and Teaching Tips, Site Updates and Special Offers Directly to Your Mailbox

Join now and get a special bonus:

First 2 chapters of the English Short Stories Book and Workbook.

Are you a teacher or a student?

* We respect your email privacy and you can unsubscribe at any time.