UK vs. US English | Difference, Spelling & Examples

When writing your dissertation, research paper or essay, you will have to consistently follow the conventions of a specific style of English. The most commonly used forms are:

  • American English
  • British English
  • Australian English

Although these dialects follow many of the same rules, they also have some important differences in spelling, punctuation and word choice.

Note
Check with your supervisor to find out if you are expected to use a specific style of English. If you are allowed to choose, pick the style that feels most natural to you. Make sure you set the correct language for your document (in Microsoft Word, select “Review” and then “Language”).

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US vs. UK spelling

As the table below shows, the difference between UK and US spelling usually relates to just one or two letters.

US UK Australia
uses -ize, -yze (e.g., realize, analyze) prefers -ise, -yse (e.g., realise, analyse), but is flexible almost always uses ise, yse
-er (e.g., theater, meter) -re (e.g., theatre, metre) British usage
uses -or (e.g., honor, color, splendor) uses -our (e.g. honour, colour, splendour) British usage
uses –ction (e.g., connection) acceptable to use –xion (e.g., connexion), but this is increasingly rare American usage
often drops -e for word modifications (e.g., judge to judgment, live to livable) generally keepse for word modifications (e.g., judge to judgement, live to liveable) keeps -e (e.g., judgement), like British; but sometimes drops -e (e.g., livable)
usually prefers -e to -oe or -ae (e.g., pediatrician, leukemia) uses -oe and -ae (e.g., paediatrician, leukaemia) British usage
usually prefers one “l” to double “ll” (e.g., canceled, traveled) uses double “ll” instead of one “l” “(e.g., cancelled, travelled) British usage (travelling vs traveling, cancelled vs canceled)

The following cheat sheet outlines the preferred spelling of some words that are commonly used in academic writing.

Verbs
US UK Australia
analyze analyse analyse
apologize apologise apologise
capitalize capitalise capitalise
categorize categorise categorise
characterize characterise characterise
colonize colonise colonise
endeavor endeavour endeavour
enroll enrol enrol
fulfill fulfil fulfil
globalize globalise globalise
honor honour honour
hypothesize hypothesise hypothesise
inquire enquire enquire
install instal install
legalize legalise legalise
maneuver manoeuvre manoeuvre
maximize maximise maximise
minimize minimise minimise
mold mould mould
neutralize neutralise neutralise
optimize optimise optimise
paralyze paralyse paralyse
plow plough plough
privatize privatise privatise
randomize randomise randomise
realize realise realise
recognize recognise recognise
Past-tense verbs
US UK Australia
canceled cancelled cancelled
channeled channelled channelled
labeled labelled labelled
modeled modelled modelled
traveled travelled travelled
Nouns
US UK Australia
acknowledgment acknowledgement acknowledgment or acknowledgement
aluminum aluminium aluminium
artifact artefact artefact
behavior behaviour behaviour
caliber calibre calibre
center centre centre
color colour colour
cooperation co-operation cooperation or co-operation
councilor councillor councillor
counselor counsellor counsellor
defense defence defence
estrogen oestrogen oestrogen
fetus foetus foetus
fiber fibre fibre
flavor flavour flavour
humor humour humour
judgment judgement judgement
labor labour labour
leukemia leukaemia leukaemia
license licence licence
liter litre litre
meter metre metre
neighbor neighbour neighbour
organization organisation organisation
paleontology palaeontology palaeontology
program programme (but program if computer-related) program
sulfur sulphur sulphur
theater theatre theatre
tire tyre tyre
vapor vapour vapour
Adjectives
US UK Australia
aging ageing ageing
favorite favourite favourite
gray grey grey
livable liveable livable
movable moveable moveable
orthopedic orthopaedic orthopaedic
salable saleable saleable
skeptical sceptical sceptical
somber sombre sombre

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US vs. UK punctuation

The main punctuation differences relate to single and double quotation marks and where to place other punctuation in relation to quotations.

US UK Australia
Double quotation marks (“x”), but alternate with single for quotations within quotations

  • She said, “This model has been called ‘the best.’”
Single quotation marks (‘x’), but alternate with double for quotations within quotations

  • She said, ‘This model has been called “the best”’.
UK usage
Punctuation appears within quotation marks

  • “The best there is,” she said.
  • She said he is “the best there is.”

except when punctuation emphasizes the writer’s sentence rather than the speaker’s quotation

  • Did she say, “the best there is”?
  • She told them we are “the best there is”!
Punctuation appears outside quotation marks

  • ‘The best there is’, she said.
  • Did she say, ‘the best there is’?

except when the punctuation is part of the original quotation rather than the speaker’s sentence.

  • She said, ‘the best there is.’
  • She asked, ‘the best there is?’
UK usage

US vs. UK verb conjugation

There are some differences in subject-verb agreement with collective nouns (nouns referring to a group of individual things as a unified whole) and in past tense verb forms.

US UK Australia
Tends to treat collective nouns as singular.

  • The team is going to win, the staff has decided
Tends to treat collective nouns as plural.

  • The team are going to win, the staff have decided
US usage
Verbs take -ed endings for simple past tense and past participles

… with the exception of common irregular verbs

  • take to took
  • hear to heard
Verbs take -ed endings for simple past tense and past participles, but with more exceptions

  • compel to compelled
  • spell to spelt
  • learn to learnt

… and irregular verbs are conjugated the same

  • take to took
  • hear to heard
UK usage

US vs. UK abbreviations

There is also disagreement over how to use periods in abbreviations.

US UK Australia
Most title abbreviations take a period.

  • Doctor to Dr.
  • Mister to Mr.
  • Honorable to Hon.
  • Drive to Dr.
Title abbreviations take a period only if the abbreviation does not end on the last letter of the full word

  • Doctor to Dr
  • Mister to Mr
  • Honourable to Hon.
  • Drive to Dr.
UK usage

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Consistency is key

Most importantly, each individual word must be spelled the same throughout your document. However, it’s also best to avoid mixing US English and UK English.

Examples: Mixing different styles of English
  • The defense minister first travelled to China in 2013.
  • The defense minister first traveled to China in 2013.
  • The defence minister first travelled to China in 2013.

In addition, the same spelling should generally be used for all forms of a word.

Examples: Mixing different styles of English
  • The organization is headquartered in Osaka, but it usually organises workshops in Tokyo.
  • The organization is headquartered in Osaka, but it usually organizes workshops in Tokyo.
  • The organisation is headquartered in Osaka, but it usually organises workshops in Tokyo.

If you use our proofreading and editing service, you can request a specific style of English (US or UK).

Why is it so complicated?

After winning their independence from the British, Americans used language as a way to create their own identity. This led to many variations in spelling and punctuation, among other things. Australia also developed its own written conventions, which lie somewhere between those of the US and the UK (although they tend to be more British).

Of the three, Australian English is generally the most flexible, and US English is the least flexible. Bear in mind that the rules are not always very firm: there are many exceptions, and the preferred conventions are constantly changing.

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