Improving Your English

British vs American spelling: Learn UK and US spelling differences

There are hundreds of words that are spelled differently in British and American English, but fortunately, most of them are covered by just a few common rules.

Here, we are going to look at the key differences between British vs American spelling, along with word lists showing over 200 examples, so you can be sure you’re communicating clearly and consistently.

woman wondering about british vs american spelling differences

8 British vs American spelling differences

UK and US spelling differs in several areas. Generally speaking, British English has retained more of the spelling of words originating from other languages (e.g. French, Greek, and Latin) whereas American English has adopted spelling that more closely reflects how the word is pronounced.

Both forms of spelling will be understood by any English reader, but it’s best to be consistent with using either American or British spelling, vocabulary, and grammar – especially if communicating professionally for work.

So, let’s take a look at the most common American and British English spelling differences that you should be aware of. We have included a list of examples and exceptions for each rule, but these are not complete lists, so we recommend consulting a dictionary if you need to check any other words.

1. British -re vs American -er

This is one of the most common spelling differences in American and British English.

An unstressed -re ending (pronounced /əɹ/) in BE becomes -er in AE. Here are some common examples:

British EnglishAmerican English
calibrecaliber
centrecenter
fibrefiber
kilometrekilometer
litreliter
lustreluster
meagremeager
ochreocher
sombresomber
theatretheater

Exceptions

Some AE words keep the -re ending for pronunciation reasons. ‘Acre’, ‘massacre’, and ‘mediocre’ need a -cre ending to show that the ‘c’ is pronounced as /k/ rather than /s/.

‘Ogre’ is another exception that keeps the -re ending in American English.

2. British -our vs American -or

Most words that end with an unstressed -our in BE change to -or in AE. For example:

British EnglishAmerican English
armourarmor
behaviourbehavior
colourcolor
demeanourdemeanor
endeavourendeavor
favourfavor
flavourflavor
harbourharbor
honourhonor
humourhumor
labourlabor
neighbourneighbor
odourodor
rumourrumor
savioursavior
tumourtumor

The same applies to derivatives of these words such as behavioural/behavioral, flavoured/flavored, humourous/humorous, and neighbouring/neighboring.

3. British -ise vs American -ize

Here’s another common difference between British and American english spelling.

Although the -ise suffix is traditionally British, many dictionaries now recognize both as acceptable. British media tends to use -ise, but the use of -ize is becoming more common. In American English, only -ize is used for these words.

Here are some common words affected by this difference in UK and US spelling:

British EnglishAmerican English
agoniseagonize
apologiseapologize
authoriseauthorize
criticisecriticize
emphasiseemphasize
energiseenergize
generalisegeneralize
harmoniseharmonize
jeopardisejeopardize
legaliselegalize
minimiseminimize
organiseorganize
penalisepenalize
plagiariseplagiarize
prioritiseprioritize
realiserealize
recogniserecognize
specialisespecialize
summarisesummarize
symbolisesymbolize
utiliseutilize

The same also applies to -yse and -yze:

British EnglishAmerican English
analyseanalyze
catalysecatalyze
electrolyseelectrolyze
paralyseparalyze

Note: As both spellings are acceptable in British English, the -ize ending may not always be picked up by a spell checker set to British spelling. Take special care to check your consistency with this one.

Exceptions

Some words take the -ize suffix in both British and American spelling. For example:

  • Capsize
  • Maize
  • Prize (n, adj)
  • Seize
  • Size

Other words take the -ise suffix in both UK and US spelling, such as:

  • Advertise
  • Advise
  • Arise
  • Concise
  • Compromise
  • Despise
  • Devise
  • Disguise
  • Enterprise
  • Exercise
  • Franchise
  • Guise
  • Merchandise
  • Otherwise
  • Revise
  • Rise
  • Supervise
  • Surmise
  • Surprise
  • Wise

4. British ‘ae’ and ‘oe’

This difference between British and American English spelling involves many words written with ‘ae’ or ‘oe’ in BE being simplified to just ‘e’ in AE. Note that these are mainly medical, scientific, and technical terms.

British EnglishAmerican English
aeoneon
amoebaameba
anaemiaanemia
anaesthesiaanesthesia
caesareancesarean
diarrhoeadiarrhea
encyclopaediaencyclopedia
foetusfetus
gonorrhoeagonorrhea
haemoglobinhemoglobin
leukaemialeukemia
manoeuvremaneuver (note the -er too)
oestrogenestrogen
paediatricpediatric

In this case, the British spelling derives from Latin and Greek roots. The extra letter was removed from these words as part of Noah Webster’s spelling reform in the 19th century, as is the case with many British vs American spelling differences.

5. Double and single ‘l’

The final ‘l’ of a word is doubled in British English when adding -ed, -ing, -or, -er, or -est. American spelling keeps a single ‘l’:

British EnglishAmerican English
cancelledcanceled
cruellestcruelest
diallingdialing
fuelledfueled
jewellerjeweler
labelledlabeled
modellingmodeling
signalledsignaled
towelledtoweled
travellertraveler

Exception: the word ‘parallel’ always keeps a single ‘l’ (e.g. paralleled, paralleling).

Conversely, some British English words that take a single ‘l’ have a double ‘l’ in American English:

British EnglishAmerican English
appalappall
distildistill
enrolenroll
fulfilfulfill
instilinstill
skilfulskillful
wilfulwillful

6. British -ogue vs American -og

This rule affects polysyllabic words ending with -gogue and -logue. Single-syllable words such as ‘rogue’ and ‘vogue’ are unaffected.

British EnglishAmerican English
analogueanalog
cataloguecatalog
dialoguedialog
epilogueepilog
monologuemonolog
pedagoguepedagog
prologueprolog

7. British -ence vs American -ense

Another example of different spelling between British and American English is with -ence and -ense suffixes. However, this one is somewhat more confusing as British English distinguishes between verbs and nouns.

A few nouns that end with -ence in British English take the -ense ending in American English. However, in both versions of the language, the corresponding verb (if there is one) is spelled with -ense.

British English (noun only)American English
defencedefense
licencelicense
offenceoffense
pretencepretense

This is one of the British vs American spelling rules that applies to only a small minority of words with this suffix. There are plenty of words spelled with -ence in American English, such as ‘absence’, ‘commence’, ‘essence’ and ‘presence’.

A similar noun/verb distinction appears with practice vs practise.

However, with advice vs advise and device vs devise, both forms of the language use -ice for the noun and -ise for the verb, which also have distinct pronunciations.

8. Miscellaneous American and British English spelling differences

Here is a final list of spelling differences between American and British English, with words that are not covered by any of the other rules mentioned above:

British EnglishAmerican English
acknowledgementacknowledgment
aluminiumaluminum
axeax
cheque (payment method)check
chillichili
cosycozy
kerb (edge of the road)curb
greygray
judgementjudgment
liquoricelicorice
mouldmold
moustachemustache
omeletteomelet
ploughplow
pyjamaspajamas
scepticskeptic
sulphursulfur
syphonsiphon
tyre (for a wheel)tire
whiskywhiskey
yoghurtyogurt

There are some additional spelling variations found in British vs American grammar differences, such as the simple past burned/burnt and spilled/spilt.

Conclusion

Here we have listed hundreds of common words that are spelled differently in American and British English, but there are hundreds more for you to discover.

Fortunately, even if you aren’t familiar with them all yet, the differences are not so severe that they are likely to cause significant miscommunications. The same cannot be said for British vs American word differences, though!

You may also want to explore Australian English, which follows most of the conventions of British English, and Canadian English, which is similar but with a stronger influence from the US in some regards.

FAQs

Why are some American and British words spelled differently?

American and British spelling differs due to historical reasons, including spelling reforms. Figures like Noah Webster introduced changes to American English spelling in the 19th century to simplify and standardize, leading to variations like color/colour.

Are British and American spelling becoming more similar?

Yes, in some ways they are. For example, it’s becoming more acceptable to use the -ize suffix in British English, whereas -ise used to be the only acceptable spelling.

However, in most of the spelling differences mentioned here, the two versions of the language remain steadfastly distinct.

Do spell checkers distinguish between UK vs US spelling?

Yes, you can set the spell checker on your laptop, phone, or tablet to British or American English (or to any other English variant you wish). This helps keep your writing consistent to one format or the other.

You probably have an autocorrect setting, but the downside of using this is that you may not notice the corrections being made, and therefore your awareness of the differences between British and American spelling is diminished.

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