American and British English spelling differences

Latin-derived spellings (often through Romance)

-our, -or

Most words ending in an unstressed ‑our in British English end in ‑or in American English. This affects the British spellings arbour, ardour, armour, behaviour, candour, clamour, clangour, colour, demeanour, dolour, enamour, endeavour, favour, fervour, flavour, harbour, honour, humour, labour, neighbour, odour, parlour, rancour, rigour, rumour, saviour, savour, splendour, succour, tumour, valour, vapour, and vigour. Wherever the vowel is unreduced in pronunciation (e.g., devour, contour, flour, paramour, tour, troubadour, and velour), however, the spelling is uniform in all English varieties.

Most words of this kind come from Latin, where their endings were spelled ‑or. They were first adopted into English from early Old French, and the ending was spelled ‑our, ‑or or ‑ur. After the Norman Conquest, the ending became ‑our to match the later Old French spelling. The ‑our ending was used not only in new English borrowings, but was also applied to the earlier borrowings that had used ‑or. However, ‑or was still sometimes found. The first three folios of Shakespeare's plays used both spellings before they were standardised to ‑our in the Fourth Folio of 1685.

After the Renaissance, new borrowings from Latin were taken up with their original ‑or ending, and many words once ending in ‑our (for example, chancellour and governour) reverted to ‑or. A few words of the ‑our/or group do not have a Latin counterpart that ends in ‑or; for example, armo(u)r, behavio(u)r, harbo(u)r, neighbo(u)r; also arbo(u)r, meaning "shelter", though senses "tree" and "tool" are always arbor, a false cognate of the other word. Some 16th- and early 17th-century British scholars indeed insisted that ‑or be used for words from Latin (e.g., color) and ‑our for French loans; however, in many cases, the etymology was not clear, and therefore some scholars advocated ‑or only and others ‑our only.

Webster's 1828 dictionary had only -or and is given much of the credit for the adoption of this form in the United States. By contrast, Johnson's 1755 (pre-US independence and establishment) dictionary used -our for all words still so spelled in the United Kingdom (like colour), but also for words where the u has since been dropped: ambassadour, emperour, errour, governour, horrour, inferiour, mirrour, perturbatour, superiour, tenour, terrour, tremour. Johnson, unlike Webster, was not an advocate of spelling reform, but chose the spelling best derived, as he saw it, from among the variations in his sources. He preferred French over Latin spellings because, as he put it, "the French generally supplied us". English speakers who moved to the United States took these preferences with them. In the early 20th century, H. L. Mencken notes that "honor appears in the 1776 Declaration of Independence, but it seems to have been put there rather by accident than by design". In Jefferson's original draft it is spelled "honour". In the United Kingdom, examples of behavior, color, flavor, harbor, and neighbor rarely appear in Old Bailey court records from the 17th and 18th centuries, whereas there are thousands of examples of their -our counterparts. One notable exception is honor. Honor and honour were equally frequent in the United Kingdom until the 17th century; honor only exists in the UK now as the spelling of Honor Oak, a district of London, and of the occasional given name Honor.

Derivatives and inflected forms

In derivatives and inflected forms of the -our/or words, British usage depends on the nature of the suffix used. The u is kept before English suffixes that are freely attachable to English words (for example in humourless, neighbourhood, and savoury) and suffixes of Greek or Latin origin that have been adopted into English (for example in behaviourism, favourite, and honourable). However, before Latin suffixes that are not freely attachable to English words, the u:

• may be dropped, for example in honorary, honorific, humorist, humorous, invigorate, laborious, and vigorous;
• may be either dropped or kept, for example in colo(u)ration and colo(u)rize or colo(u)rise; or
• may be kept, for example in colourist.

In American usage, derivatives and inflected forms are built by simply adding the suffix in all cases (for example, favorite, savory etc.) since the u is absent to begin with.

Exceptions

American usage, in most cases, keeps the u in the word glamour, which comes from Scots, not Latin or French. Glamor is sometimes used in imitation of the spelling reform of other -our words to -or. The adjective glamorous often drops the first "u". Saviour is a somewhat common variant of savior in the US. The British spelling is very common for honour (and favour) in the formal language of wedding invitations in the US. The name of the Space Shuttle Endeavour has a u in it because the spacecraft was named after British Captain James Cook's ship, HMS Endeavour. The (former) special car on Amtrak's Coast Starlight train is known as the Pacific Parlour car, not Pacific Parlor. Proper names such as Pearl Harbor or Sydney Harbour are usually spelled according to their native-variety spelling vocabulary.

The name of the herb savory is spelled thus everywhere, although the related adjective savo(u)ry, like savo(u)r, has a u in the UK. Honor (the name) and arbor (the tool) have -or in the United Kingdom, as mentioned above, as does the word pallor. As a general noun, rigour has a u in the UK; the medical term rigor (sometimes ) does not, such as in rigor mortis, which is Latin. Derivations of rigour/rigor such as rigorous, however, are typically spelled without a u, even in the UK. Words with the ending -irior, -erior or similar are spelled thus everywhere. Junior and senior were borrowed directly from Latin in the 13th century (as adjectives for father-son namesakes), and have never had -our forms anywhere.

The word armour was once somewhat common in American usage but has disappeared except in some brand names such as Under Armour.

The agent suffix -or (separator, elevator, translator, animator, etc.) is spelled thus both in American and British English.

Commonwealth usage

Commonwealth countries normally follow British usage. Canadian English most commonly uses the -our ending and -our- in derivatives and inflected forms. Owing to close geographic and business ties with the United States, -or endings are also sometimes used. Throughout the late 19th and early to mid-20th century, most Canadian newspapers chose to follow the American usage of -or endings, originally to save time and money in the era of manual movable type. However, in the 1990s, the majority of Canadian newspapers officially updated their spelling policies to the British usage of -our. This coincided with a renewed interest in Canadian English, and the release of the updated Gage Canadian Dictionary in 1997 and the first Canadian Oxford Dictionary in 1998. Historically, most libraries and educational institutions in Canada have supported the use of the Oxford English Dictionary rather than the American Webster's Dictionary.

In Australia, -or endings enjoyed some use throughout the 19th century and in the early 20th century. Like Canada, though, most major Australian newspapers have switched from "-or" endings to "-our" endings. The "-our" spelling is taught in schools nationwide as part of the Australian curriculum. The most notable countrywide use of the -or ending is for one of the country's major political parties, the Australian Labor Party, which was originally named "the Australian Labour Party" in 1908, but was frequently referred to as both "Labour" and "Labor". The "Labor" spelling was adopted from 1912 onward due to the influence of the American labor movement and King O'Malley. On top of that, some place names in South Australia such as Victor Harbor, Franklin Harbor or Outer Harbor are usually spelled with the -or spellings. Aside from that, -our is now almost universal in Australia but the -or endings remain a minority variant. New Zealand English, while sharing some words and syntax with Australian English, follows British usage.

-re, -er

In British English, some words from French, Latin or Greek end with a consonant followed by an unstressed -re (pronounced ). In modern American English, most of these words have the ending -er. The difference is most common for words ending in -bre or -tre: British spellings accoutre (see exceptions), bistre, calibre, centre, dioptre, fibre, goitre, litre, louvre, lustre, manoeuvre, meagre, metre (length), mitre, nitre, ochre, philtre, reconnoitre, sabre, saltpetre, sceptre, sepulchre, sombre, spectre, theatre (see exceptions) and titre all have -er in American spelling.

In the United Kingdom, both -re and -er spellings were common before Johnson's 1755 dictionary was published. Following this, -re became the most common usage in the United Kingdom. In the United States, following the publication of Webster's Dictionary in the early 19th century, American English became more standardized, exclusively using the -er spelling.

In addition, the spelling of some words have been changed from -re to -er in both varieties. These include amber, blister, cadaver, canister, chamber, chapter, charter, cider, coffer, coriander, cover, cucumber, cylinder, December, diaper, disaster, enter, fever, filter, gender, leper, letter, lobster, master, member, meter (measuring instrument), minister, monster, murder, November, number, October, offer, order, oyster, powder, proper, render, semester, September, sequester, sinister, sober, surrender, tender, and tiger. Words using the -meter suffix (from Ancient Greek -μέτρον métron, via French -mètre) normally had the -re spelling from earliest use in English but were superseded by -er. Examples include thermometer and barometer.

The e preceding the r is kept in American-inflected forms of nouns and verbs, for example, fibers, reconnoitered, centering, which are fibres, reconnoitred, and centring respectively in British English. According to the OED, centring is a "word ... of 3 syllables (in careful pronunciation)" (i.e., ), yet there is no vowel in the spelling corresponding to the second syllable (). The OED third edition (revised entry of June 2016) allows either two or three syllables. On the Oxford Dictionaries Online website, the three-syllable version is listed only as the American pronunciation of centering. The e is dropped for other derivations, for example, central, fibrous, spectral. However, the existence of related words without e before the r is not proof for the existence of an -re British spelling: for example, entry and entrance come from enter, which has not been spelled entre for centuries.

The difference relates only to root words; -er rather than -re is universal as a suffix for agentive (reader, user, winner) and comparative (louder, nicer) forms. One outcome is the British distinction of meter for a measuring instrument from metre for the unit of length. However, while "poetic metre" is often spelled as -re, pentameter, hexameter, etc. are always -er.

Exceptions

Many other words have -er in British English. These include Germanic words, such as anger, mother, timber and water, and such Romance-derived words as danger, quarter and river.

The ending -cre, as in acre, lucre, massacre, and mediocre, is used in both British and American English to show that the c is pronounced rather than . The spellings euchre and ogre are also the same in both British and American English.

The spelling theatre is a variant in American English. It appears frequently in names, such as those of many New York City theatres on Broadway, especially of things named when it was still the prevailing spelling. (In British English a "theatre" is where stage performances take place but not film screenings – these take place in a cinema, or "picture theatre" in Australia.)

It is sometimes claimed that, in the US, these two spellings have different meanings, with theatre referring to dramatic arts and theater referring to buildings. However, the trade magazine American Theatre described this as a "popular myth", as theater is the prevailing American spelling used to refer to both dramatic arts and buildings. National US newspapers such as The New York Times use theater in their entertainment sections; the Times even corrects proper names from theatre to theater. The spelling theatre was previously more common, prevailing into at least the 1960s, with organizations such as Theatre Communications Group, founded 1961, and The Guthrie Theater, founded 1963, using it. The New York Times switched to using theater in 1962, The Guthrie changed its spelling in 1971, and the spelling has become increasingly common since.

Some placenames in the United States use Centre in their names. Examples include the villages of Newton Centre and Rockville Centre, the city of Centreville, Centre County and Centre College. Sometimes, these places were named before spelling changes but more often the spelling serves as an affectation. Proper names are usually spelled according to their native-variety spelling vocabulary; so, for instance, although Peter is the usual form of the male given name, as a surname both the spellings Peter and Petre (the latter notably borne by a British lord) are found.

For British accoutre, the American practice varies: the Merriam-Webster Dictionary prefers the -re spelling, but The American Heritage Dictionary of the English Language prefers the -er spelling.

More recent French loanwords keep the -re spelling in American English. These are not exceptions when a French-style pronunciation is used ( rather than ), as with double entendre, genre and oeuvre. The unstressed pronunciation of an -re ending is used either as the most common variant or an alternative pronunciation with some words, including cadre, macabre, maître d', Notre Dame, piastre, and timbre.

Commonwealth usage

The -re endings are mostly standard throughout the Commonwealth. The -er spellings are recognized as minor variants in Canada, partly due to US influence. They are sometimes used in proper names.

-ce, -se

For advice/advise and device/devise, American English and British English both keep the noun–verb distinction both graphically and phonetically (where the pronunciation is - for the noun and - for the verb). For licence/license or practice/practise, British English also keeps the noun–verb distinction graphically (although phonetically the two words in each pair are homophones with - pronunciation). On the other hand, American English uses license and practice for both nouns and verbs (with - pronunciation in both cases too).

American English has kept the Anglo-French spelling for defense and offense, which are defence and offence in British English. Likewise, there are the American pretense and British pretence; but derivatives such as defensive, offensive, and pretension are always thus spelled in both systems.

Australian and Canadian usages generally follow British usage.

-xion, -ction

The spelling connexion is now rare in everyday British usage, its use lessening as knowledge of Latin attenuates, and it has almost never been used in the US: the more common connection has become the standard worldwide. According to the Oxford English Dictionary, the older spelling is more etymologically conservative, since the original Latin word had -xio-. The American usage comes from Webster, who abandoned -xion and preferred -ction. Connexion was still the house style of The Times of London until the 1980s and was still used by Post Office Telecommunications for its telephone services in the 1970s, but had by then been overtaken by connection in regular usage (for example, in more popular newspapers). Connexion (and its derivatives connexional and connexionalism) is still in use by the Methodist Church of Great Britain to refer to the whole church as opposed to its constituent districts, circuits and local churches, whereas the US-based United Methodist Church uses Connection.

Complexion (from complex) is the standard form worldwide, though complection does exist as an uncommon variant. The adjective complected (as in "dark-complected"), although sometimes proscribed, is on equal footing in the United States with complexioned. It is not used in this way in the UK, although there exists a rare alternative meaning of complicated.

Greek-derived and Latin-derived spellings

ae and oe

In American English, medical terms that are written with ae/æ or oe/œ in British English are written only with an e. Examples are (with the non-American letter in bold): anaemia, anaesthesia, caecum, coeliac, diarrhoea, faeces, foetal, gynaecology, haemoglobin, haemophilia, leukaemia, oesophagus, oestrogen, orthopaedic, paediatric. The chemical haem (named as a shortening of haemoglobin) is spelled heme in American English, to avoid confusion with hem.

Canadian English mostly follows American English in this respect, although it is split on gynaecology (e.g. Society of Obstetricians and Gynaecologists of Canada vs. the Canadian Medical Association's Canadian specialty profile of obstetrics/gynecology). Pediatrician is preferred roughly 10 to 1 over paediatrician, while foetal and oestrogen are similarly uncommon.

Additionally, there are non-medical terms that follow this rule: aeon, caesium, encyclopaedia, manoeuvre, palaeontology and paedophile. Oenology is acceptable in American English, but is considered a minor variant of enology, whereas although ameba, archeology and esthetic exist in American English, the British spellings amoeba, archaeology and aesthetic prevail. The same is the case for paean, palaestra, phoenix and subpoena.

Words that can be spelled either way in British English include chamaeleon, encyclopaedia, homoeopathy, mediaeval (a minor variant in both AmE and BrE), foetid and foetus. The spellings foetus and foetal are Britishisms based on a mistaken etymology. The etymologically correct original spelling fetus reflects the Latin original and is the standard spelling in medical journals worldwide; the Oxford English Dictionary notes that "In Latin manuscripts both fētus and foetus are used".

The Ancient Greek diphthongs <αι> and <οι> were transliterated into Latin as <ae> and <oe>. The ligatures æ and œ were introduced when the sounds became monophthongs, and were later applied to words not of Greek origin in both Latin (for example, cœli)) and French (for example, œuvre). In English, which has adopted words from all three languages, it is now usual to replace Æ/æ with Ae/ae and Œ/œ with Oe/oe. In many words, the digraph has been reduced to a lone e in all varieties of English: for example, oeconomics, praemium, and aenigma. In other cases, the digraph is retained across all varieties. Despite phoenix and subpoena being the most common spellings in American English, the uncommon variants phenix and subpena are occasionally used, with Phenix in Virginia illustrating the variant spelling. The retention of the digraph is especially common in names: Aegean (the sea), Caesar, Oedipus, Phoebe, etc., although "caesarean section" may be spelled as "cesarean section". There is no reduction of Latin -ae plurals (e.g., larvae); nor where the digraph <ae>/<oe> does not result from the Greek-style ligature as, for example, in maelstrom or toe; the same is true for the British form aeroplane (compare other aero- words such as aerosol). The now chiefly North American airplane is not a respelling but a recoining, modelled after airship and aircraft. The word airplane dates from 1907, at which time the prefix aero- was trisyllabic, often written aëro-.

Commonwealth usage

In Canada, oe and ae are sometimes found in academic and scientific writing as well as government publications (for example, the fee schedule of the Ontario Health Insurance Plan) and some words such as palaeontology or aeon. In Australia, it can go either way, depending on the word: for instance, medieval is spelled with the e rather than ae, following the American usage along with numerous other words such as eon or fetus, while other words such as oestrogen or paediatrician are spelled the British way. The Macquarie Dictionary also notes a growing tendency towards replacing ae and oe with e worldwide and with the exception of manoeuvre, all British or American spellings are acceptable variants. Elsewhere, the British usage prevails, but the spellings with just e are increasingly used. Manoeuvre is the only spelling in Australia, and the most common one in Canada, where maneuver and manoeuver are also sometimes found.

One exception is that while British and American English both use the spelling "palaeolithic", the Canadian English standard spelling is "paleolithic", which is one of the very few instances where the Canadian spelling of a word differs from both the British and American spellings of that word.

Greek-derived spellings (often through Latin and Romance)

-ise, -ize (-isation, -ization)

Origin and recommendations

The -ize spelling is often incorrectly seen in the United Kingdom as an Americanism. It has been in use since the 15th century, predating the -ise spelling by over a century. The verb-forming suffix -ize comes directly from Ancient Greek -ίζειν (-ízein) or Late Latin -izāre, while -ise comes via French -iser, which itself stems from the same Greek suffix. The Oxford English Dictionary (OED) recommends -ize and lists the -ise form as an alternative.

Publications by Oxford University Press (OUP)—such as Henry Watson Fowler's A Dictionary of Modern English Usage, Hart's Rules, and The Oxford Guide to English Usage—also recommend -ize. However, Robert Allan's Pocket Fowler's Modern English Usage considers either spelling to be acceptable anywhere but the US.

Usage

American spelling avoids -ise endings in words like organize, realize and recognize.

British spelling mostly uses -ise (organise, realise, recognise), though -ize is sometimes used. The ratio between -ise and -ize stood at 3:2 in the British National Corpus up to 2002. The spelling -ise is more commonly used in UK mass media and newspapers, including The Times (which switched conventions in 1992), The Daily Telegraph, The Economist and the BBC. The Government of the United Kingdom additionally uses -ise, stating "do not use Americanisms" justifying that the spelling "is often seen as such". The -ize form is known as Oxford spelling and is used in publications of the Oxford University Press, most notably the Oxford English Dictionary, and of other academic publishers such as Nature, the Biochemical Journal and The Times Literary Supplement. It can be identified using the IETF language tag en-GB-oxendict (or, historically, by en-GB-oed).

In Ireland, India, Australia, and New Zealand -ise spellings strongly prevail: the -ise form is preferred in Australian English at a ratio of about 3:1 according to the Macquarie Dictionary.

In Canada, the -ize ending is more common, although the Ontario Public School Spelling Book spelled most words in the -ize form, but allowed for duality with a page insert as late as the 1970s, noting that, although the -ize spelling was in fact the convention used in the OED, the choice to spell such words in the -ise form was a matter of personal preference; however, a pupil having made the decision, one way or the other, thereafter ought to write uniformly not only for a given word, but to apply that same uniformity consistently for all words where the option is found. Just as with -yze spellings, however, in Canada the ize form remains the preferred or more common spelling, though both can still be found, yet the -ise variation, once more common amongst older Canadians, is employed less and less often in favour of the -ize spelling. (The alternate convention offered as a matter of choice may have been due to the fact that although there were an increasing number of American- and British-based dictionaries with Canadian Editions by the late 1970s, these were largely only supplemental in terms of vocabulary with subsequent definitions. It was not until the mid-1990s that Canadian-based dictionaries became increasingly common.)

Worldwide, -ize endings prevail in scientific writing and are commonly used by many international organizations, such as United Nations Organizations (such as the World Health Organization and the International Civil Aviation Organization) and the International Organization for Standardization (but not by the Organisation for Economic Co-operation and Development). The European Union's style guides require the usage of -ise. Proofreaders at the EU's Publications Office ensure consistent spelling in official publications such as the Official Journal of the European Union (where legislation and other official documents are published), but the -ize spelling may be found in other documents.

The same applies to inflections and derivations such as colonised/colonized and modernisation/modernization.

Exceptions

• Some verbs take only an -ize form worldwide. In these, -ize is not a suffix, so does not ultimately come from Ancient Greek -ίζειν: for example, capsize, seize (except in the legal phrases to be seised of or to stand seised to), size and prize (meaning value, as opposed to the prise that means pry).
• Some verbs take only -s- worldwide. In these, -ise is not a suffix, but part of the English, French or Latin stems -mise-, -rise, -vise, etc.: advise, arise, chastise, circumcise, compromise, demise, despise, devise, disguise, excise, exercise, franchise, guise, improvise, incise, promise, reprise, revise, rise, surmise, televise, and wise. Less common -ize variants such as advertize, comprize, and surprize do exist in American English, but are rarer than the -ise forms.
• Some words spelled with -ize in American English are not used in British English. For example, from the noun burglar, the usual verb is formed by suffixation in American English (burglarize) but back-formation in British English (burgle).
• Conversely, the verb to prise (meaning "to force" or "to lever") is rarely used in North American English: pry is instead used, a back-formation from or alteration of prise to avoid confusion with the more common noun "prize". When it is used in Canada, it is spelled with an s, just as it is in British, Irish, Indian, New Zealand and European English, where its use is more common. However, the rare occurrences in the US have the spelling as prize even though it does not contain a suffix, so does not derive from -ίζειν.
• The spelling enterprize was the dominant spelling throughout the 18th century; Royal Navy vessels such as HMS Enterprize (1743) also used this spelling. However, enterprize is now considered archaic and is no longer used in either British or American English.

-yse, -yze

The ending -yse is now British and -yze is American. Thus, in British English analyse, catalyse, hydrolyse and paralyse, but in American English analyze, catalyze, hydrolyze and paralyze.

Either ending is derived from the Greek noun stem λύσις lysis ("release") with the -ize/-ise suffix added to it, and not the original verb form, whose stem is λυ- ly- without the -s/z- segment. The Oxford English Dictionary states on that matter:

On Greek analogies the verb would have been analysize, French analysiser, of which [French] analyser was practically a shortened form, since, though following the analogy of pairs like annexe, annexe-r, it rested chiefly on the fact that by form-association it appeared already to belong to the series of factitive verbs in French -iser, English -ize, = Latin -īzāre, from Greek -ίζ-ειν, to which in sense it belonged. Hence from the first it was commonly written in Eng. analyze, the spelling accepted by Johnson, and historically quite defensible.

Alongside the authoritative Samuel Johnson’s Dictionary, 1755, the spelling analyze was also preferred by John Kersey's of 1702 and Nathan Bailey's of 1721, both published in London. It is also given (alongside with analyse) as one of the two equally significant "main forms" in the first (published 1884-1928) and second (published 1989) editions of the Oxford English Dictionary.

In Canada, -yze is now generally preferred, but -yse is also very common. In South Africa, Australia and New Zealand, -yse is the prevailing form.

-ogue, -og

British and other Commonwealth English use the ending -logue while American English commonly uses the ending -log for words like analog(ue), catalog(ue), homolog(ue), etc., etymologically derived from Greek -λόγος -logos ("one who speaks (in a certain manner)"). The -gue spelling, as in catalogue, is used in the US, but catalog is more common. In contrast, dialogue, epilogue, prologue, and monologue are extremely common spellings compared to dialog etc. in American English, although both forms are treated as acceptable ways to spell the words (thus, the inflected forms, cataloged and cataloging vs. catalogued and cataloguing).

In American English, analog is the standard spelling for the adjective (e.g., analog signal), while analogue is sometimes preferred for the noun. According to Merriam-Webster's Collegiate Dictionary, analog is listed as the primary adjective form, and analogue as the principal noun form, with analog being labeled as a variant.

In Australia, analog is standard for the adjective, but both analogue and analog are current for the noun; in all other cases the -gue endings strongly prevail, for example monologue, except for such expressions as dialog box in computing, which are also used in other Commonwealth countries. In Australia, analog is used in its technical and electronic sense, as in analog electronics. In Canada and New Zealand, analogue is used, but analog has some currency as a technical term (e.g., in electronics, as in "analog electronics" as opposed to "digital electronics" and some video-game consoles might have an analog stick). The -ue is absent worldwide in related words like analogy, analogous, and analogist.

Words such as demagogue, pedagogue, and synagogue, from the Greek noun ἀγωγός agōgos ("guide"), are more commonly spelled with ‑ue in American English, though the shorter forms demagog, pedagog, and synagog also exist and are accepted variants.

Both British and American English use the spelling -gue with a silent -ue for certain words that are not part of the -ogue set, such as tongue, plague, vague, and league. In addition, when the -ue is not silent, as in the words argue, ague and segue, all varieties of English use -gue.

Doubled consonants

The plural of the noun bus is usually buses, with busses a minor American variant. Conversely, inflections of the verb bus usually double the s in British usage (busses, bussed, bussing) but not American usage (buses, bused, busing). In Australia, both are common, with the American usage slightly more common.

Doubled in British English

The final consonant of an English word is sometimes doubled in both American and British spelling when adding a suffix beginning with a vowel, for example strip/stripped, which prevents confusion with stripe/striped and shows the difference in pronunciation (see digraph). Generally, this happens only when the word's final syllable is stressed and when it also ends with a lone vowel followed by a lone consonant. In British English, however, a final -l is often doubled even when the final syllable is unstressed. This exception is no longer usual in American English, seemingly because of Noah Webster. The -ll- spellings are nevertheless still deemed acceptable variants by both Merriam-Webster Collegiate and American Heritage dictionaries.

• The British English doubling is used for all inflections (-ed, -ing, -er, -est) and for the noun suffixes -er and -or. Therefore, British English usage is cancelled, counsellor, cruellest, labelled, modelling, quarrelled, signalling, traveller, and travelling. Americans typically use canceled, counselor, cruelest, labeled, modeling, quarreled, signaling, traveler, and traveling. However, for certain words such as cancelled, the -ll- spelling is acceptable in American English as well.
  • The word parallel keeps a single -l- in British English, as in American English (paralleling, unparalleled), to avoid the cluster -llell-.
  • Words with two vowels before a final l are also spelled with -ll- in British English before a suffix when the first vowel either acts as a consonant (equalling and initialled; in the United States, equaling or initialed), or belongs to a separate syllable (British di•alled and fu•el•ling; American di•aled and fue•ling).
    • British woollen is a further exception due to the double vowel (American: woolen). Also, wooly is accepted in American English, though woolly prevails in both systems.
    • The verb surveil, a back-formation from surveillance, always makes surveilled, surveilling.
• Endings -ize/-ise, -ism, -ist, -ish usually do not double the l in British English; for example, devilish, dualism, normalise, and novelist.
  • Exceptions: duellist, medallist, panellist, tranquillise, and sometimes triallist in British English.
• For -ous, British English has a single l in scandalous and perilous, but the "ll" in libellous and marvellous.
• For -ee, British English has libellee.
• For -age, British English has pupillage but vassalage.
• American English sometimes has an unstressed -ll-, as in the UK, in some words where the root has -l. These are cases where the change happens in the source language, which was often Latin. (Examples: bimetallism, cancellation, chancellor, crystallize, excellent, raillery, and tonsillitis.)
• All forms of English have compelled, excelling, propelled, rebelling (stressed -ll-); revealing, fooling (double vowel before the l); and hurling (consonant before the l).
• Canadian and Australian English mostly follow British usage.

Among consonants other than l, practice varies for some words, such as where the final syllable has secondary stress or an unreduced vowel. In the United States, the spellings kidnaped and worshiped, which were introduced by the Chicago Tribune in the 1920s, are common, but kidnapped and worshipped prevail. Kidnapped and worshipped are the only standard British spellings. However, focused is the predominant spelling in both British and American English, focussed being just a minor variant in British English.

Miscellaneous:

• British calliper or caliper; American caliper.
• British jewellery; American jewelry. The word originates from the Old French word jouel (whose contemporary French equivalent is joyau, with the same meaning). The standard pronunciation does not reflect this difference, but the non-standard pronunciation (which exists in New Zealand and the United Kingdom, hence the Cockney rhyming slang word tomfoolery ) does. According to Fowler, jewelry used to be the "rhetorical and poetic" spelling in the UK, and was still used by The Times into the mid-20th century. Canada has both, but jewellery is more often used. Likewise, the Commonwealth (including Canada) has jeweller and the US has jeweler for a jewel(le)ry seller.

Doubled in American English

Conversely, there are words where British writers prefer a single l and Americans a double l. In American usage, the spelling of words is usually not changed when they form the main part (not prefix or suffix) of other words, especially in newly formed words and in words whose main part is in common use. Words with this spelling difference include appall, enrollment, fulfillment, installment, skillful, thralldom, willful. These words have monosyllabic cognates always written with -ll: pall (verb), roll, fill, stall, skill, thrall, will. Cases where a single l nevertheless occurs in both American and British English include null→annul, annulment; till→until (although some prefer til to reflect the single l in until, sometimes using a leading apostrophe ('til); this should be considered a hypercorrection as till predates the use of until); and others where the connection is not clear or the monosyllabic cognate is not in common use in American English (e.g., null is used mainly as a technical term in law, mathematics, and computer science).

In the UK, a single l is generally preferred over American forms distill, enroll, enthrall, and instill, although ll was formerly used; these are always spelled with ll in American usage. The former British spellings dulness, fulness, and instal are now quite rare. The Scottish tolbooth is cognate with tollbooth, but it has a distinct meaning.

In both American and British usages, words normally spelled -ll usually drop the second l when used as prefixes or suffixes, for example all→almighty, altogether; full→handful, useful; well→welcome, welfare; chill→chilblain.

Both the British fulfil and the American fulfill never use -ll- in the middle (i.e., *fullfill and *fullfil are incorrect).

Johnson wavered on this issue. His dictionary of 1755 lemmatizes distil and instill, downhil and uphill.

Dropped "e"

British English sometimes keeps a silent "e" when adding suffixes where American English does not.

• When adding -ing to the verbs route, singe, swinge, dye, British English usually preserves the -e to distinguish from the -ing forms of rout, sing, swing, die. This is rare in American English except for swingeing. In contrast, the verb bathe and the British verb bath both form bathing. Of other -inge verbs, both forms of English vary for tinge and twinge, and prefer cringing, hinging, lunging, syringing.
• British prefers ageing, American usually aging. Both prefer ageism, but agism is also seen in American, though uncommon.
• Before -able, British English prefers likeable, liveable, rateable, saleable, sizeable, unshakeable, where American practice prefers to drop the "-e"; but both British and American English prefer breathable, curable, datable, lovable, movable, notable, provable, quotable, scalable, solvable, usable, and those where the root is polysyllabic, like believable or decidable. Both systems keep the silent "e" when it is needed to preserve a soft "c", "ch", or "g", such as in cacheable, changeable, traceable; both usually keep the "e" after "-dge", as in knowledgeable, unbridgeable, and unabridgeable ("These rights are unabridgeable").
• Both abridgment and the more regular abridgement are current in the US, only the latter in the UK. Likewise for the word lodg(e)ment. Both judgment and judgement are in use interchangeably everywhere, although the former prevails in the US and the latter prevails in the UK except in the legal profession, where judgment is standard. This also holds for abridgment and acknowledgment. Both systems prefer fledgling to fledgeling, but ridgeling to ridgling. Acknowledgment, acknowledgement, abridgment and abridgement are all used in Australia; the shorter forms are endorsed by the Australian Capital Territory Government. As a rule, "g" is hard unless followed by an "e", "i", or "y": aside from the preceding -dg- words, the few exceptions include mortgagor, gaol, margarine (variant), and such Latin æ words as algae.
• Suffix or pseudo-suffix -y in short words varies in both Englishes; cases where British dictionaries give priority to -ey and American ones do not include fog(e)y, gam(e)y, mous(e)y, phon(e)y, pric(e)y, rop(e)y, stag(e)y.

Different spellings for different meanings

Different spellings for different pronunciations

In a few cases, essentially the same word has a different spelling that reflects a different pronunciation.

As well as the miscellaneous cases listed in the following table, the past tenses of some irregular verbs differ in both spelling and pronunciation, as with smelt (UK) versus smelled (US) (see American and British English grammatical differences: Verb morphology).

Past tense differences

In the UK, Ireland, Australia, New Zealand and Canada, it is more common to end some past tense verbs with a "t" as in learnt or dreamt rather than learned or dreamed, though such spellings are also found in American English. However, in American English, burned and burnt have different usages.

Several verbs have different past tenses or past participles in American and British English:

• The past tense of the verb "to dive" is most commonly found as "dived" in British and New Zealand English. "Dove" is sometimes used in its place in American English. Both terms are understood in Canada and Australia, and may be found either in minority use or in regional dialect in the US.
• The past tense of the verb "to get" is "got" everywhere, but the past participle is "got" in British and New Zealand English but "gotten" in American and Canadian, and occasionally in Australian English. Both terms are understood, and may be found either in minority use or in regional dialect. One exception is in the phrase "ill-gotten", which is widely used everywhere. Another is the universal use of "have got" to indicate possession or necessity: "I have got a car", "I have got to go" (whereas "I have gotten a car" would mean "I have obtained a car", and "I have gotten to go" would mean "I have had the opportunity/privilege to go"). None of this affects "forget" and "beget", whose past participles are "forgotten" and "begotten" in all varieties.

Miscellaneous spelling differences

In the table below, the main spellings are above the accepted alternative spellings.

Compounds and hyphens

British English often prefers hyphenated compounds, such as anti-smoking, whereas American English discourages the use of hyphens in compounds where there is no compelling reason, so antismoking is much more common. Many dictionaries do not point out such differences. Canadian and Australian usage is mixed, although Commonwealth writers generally hyphenate compounds of the form noun plus phrase (such as editor-in-chief). Commander-in-chief prevails in all forms of English.

Compound verbs in British English are hyphenated more often than in American English.

• any more or anymore: in the sense "any longer", the single-word form is usual in North America and Australia but unusual elsewhere, at least in formal writing. Other senses always have the two-word form; thus, Americans distinguish "I couldn't love you anymore [so I left you]" from "I couldn't love you any more [than I already do]". In Hong Kong English, any more is always two words.
• for ever or forever: traditional British English usage makes a distinction between for ever, meaning for eternity (or a very long time into the future), as in "If you are waiting for income tax to be abolished you will probably have to wait for ever"; and forever, meaning continually, always, as in "They are forever arguing". In British usage, however, forever prevails in the "for eternity" sense as well, in spite of several style guides maintaining the distinction. American writers usually use forever regardless of which sense they intend (although forever in the sense of "continually" is comparatively rare in American English, having been displaced by always).
• near by or nearby: some British writers make the distinction between the adverbial near by, which is written as two words, as in, "No one was near by"; and the adjectival nearby, which is written as one, as in, "The nearby house". In American English, the one-word spelling is standard for both forms.
• per cent or percent: it can be correctly spelled as either one or two words, depending on the Anglophone country, but either spelling must always be consistent with its usage. British English predominantly spells it as two words, so does English in Ireland and countries in the Commonwealth of Nations such as Australia, Canada, and New Zealand. American English predominantly spells it as one word. Historically, it was spelled as two words in the United States, but its usage is diminishing; nevertheless it is a variant spelling in American English. The spelling difference is reflected in the style guides of newspapers and other media agencies in the US, Ireland, and countries of the Commonwealth of Nations.

Capitalization

Acronyms pronounced as words are often written in title case by Commonwealth writers, but usually as upper case by Americans: for example, Nasa / NASA or Unicef / UNICEF. This does not apply to abbreviations that are pronounced as individual letters (referred to by some as "initialisms"), such as US, IBM, or PRC (the People's Republic of China), which are virtually always written as upper case. However, sometimes title case is still used in the UK, such as Pc (Police Constable).

Some initials are usually upper case in the US but lower case in the UK: liter/litre and its compounds (2 L or 25 mL vs 2 l or 25 ml); and ante meridiem and post meridiem (10 P.M. or 10 PM vs 10 p.m. or 10 pm). Both AM/PM and a.m./p.m. are acceptable in American English, but US style guides overwhelmingly prefer a.m./p.m.

Punctuation

The use of quotation marks, also called inverted commas or speech marks, is complicated by the fact that there are two kinds: single quotation marks (') and double quotation marks ("). British usage, at one stage in the recent past, preferred single quotation marks for ordinary use, but double quotation marks are again now increasingly common; American usage has always preferred double quotation marks, as have Canadian, Australian, and New Zealand English. It is the practice to alternate the type of quotation marks used where there is a quotation within a quotation.

The convention used to be, and in American English still is, to put full stops (periods) and commas inside the quotation marks, irrespective of the sense. British style now prefers to punctuate according to the sense, in which punctuation marks only appear inside quotation marks if they were there in the original. Formal British English practice requires a full stop to be put inside the quotation marks if the quoted item is a full sentence that ends where the main sentence ends, but it is common to see the stop outside the ending quotation marks.

Contractions where the final letter is present are often written in British English without full stops/periods (Mr, Mrs, Dr, Fr, and St — for "Saint" but not for "Street"). Abbreviations where the final letter is not present generally do take full stops/periods (such as vol., etc., i.e., ed.); British English shares this convention with French: Mlle, Mme, Dr, Ste, but M. for Monsieur. In American and Canadian English, abbreviations like St., Ave., Mr., Mrs., Ms., Dr., and Jr., usually require full stops/periods.