US, UK and Australian spelling differences: the complete teacher list

Which spelling should I use?

Pick the convention your students read every day and use it consistently across a worksheet. The safe rule of thumb: the United States uses American spelling; the United Kingdom, Australia and New Zealand share British (international) spelling; Canada is a genuine hybrid, mostly British for word endings but American for others (more on that below).

Consistency matters more than any single choice. Mixing colour with center on the same page is what looks wrong to a reader, not the variant itself. On SproutSheets you set a country once and worksheet text follows it, so a class in Sydney sees colour and metre while a class in Texas sees color and meter.

• United States: American spelling (color, center, organize, math).
• UK, Australia, New Zealand: international spelling (colour, centre, organise, maths).
• Canada: mixed (colour and centre, but organize and math).

-our vs -or (colour / color)

American English drops the u: color, favor, honor, labor, neighbor, humor, flavor, harbor, behavior, rumor, vapor. British, Australian, NZ and Canadian English keep it: colour, favour, honour, labour, neighbour, humour, flavour, harbour, behaviour.

The trap: even in British spelling the u is often dropped before certain suffixes. Honour becomes honorary and honorific, humour becomes humorous, vigour becomes vigorous, and colour becomes coloration in scientific use. The u stays for the everyday forms (colourful, favourite, neighbourhood, labourer) and disappears mainly before -ous, -ary, -ific and -ation.

-re vs -er (centre / center)

British spelling ends these words in -re where American ends in -er: centre, metre, litre, theatre, fibre, calibre, sombre, spectre, meagre. Canada keeps the -re forms too (centre, metre, theatre).

The trap teachers should know: in British and Australian English, metre is the unit of length (and the rhythm of a poem), while meter is a measuring device. So you run 100 metres but read the gas meter and the parking meter, and a thermometer is spelled -meter everywhere. American English uses meter for both. Words that end in -cre never change: acre, massacre and mediocre are spelled the same on both sides.

-ise vs -ize (organise / organize)

This is the one most people get slightly wrong. Australia and New Zealand strongly prefer -ise: organise, realise, recognise, apologise, memorise, categorise. American English uses -ize: organize, realize, recognize. Canada follows the American -ize.

The surprise: -ize is not simply American. It is also valid British spelling, the house style of the Oxford English Dictionary and Oxford University Press, on the grounds that the suffix comes from the Greek -izo. So both organise and organize are correct in the UK, but -ise is far more common in general British use and is the norm in Australia. If you are writing for an Australian classroom, choose -ise.

• Always -ise, never -ize, in every variety (these do not come from the Greek suffix): advertise, advise, comprise, compromise, devise, despise, exercise, improvise, revise, supervise, surprise, televise, disguise.
• Always -ize in every variety: capsize, prize (the reward), seize (a special case with -ei-).
• The -yse family follows the same split: British and Australian analyse, paralyse and catalyse become American analyze, paralyze and catalyze. Canada uses the American -yze.

-ogue vs -og (catalogue / catalog)

British, Australian, NZ and Canadian English keep the full -ogue ending: catalogue, dialogue, analogue, monologue, epilogue, prologue. American English often shortens it to -og (catalog, dialog, analog), though the longer forms are still used and -logue survives in words like travelogue. In computing, dialog box and analog signal are common everywhere.

Single vs double L (travelling / traveling), and the reversal

When you add -ing, -ed, -er or -ous to a word ending in a single vowel plus l, British and Australian English double the l regardless of stress, while American English usually does not: travelling and traveller, cancelled, modelling, labelling, marvellous, jewellery and jeweller, counselling, fuelling, signalling.

The reversal that catches everyone: with a handful of base words the doubling goes the other way, so American English has the extra l. British and Australian English write fulfil, enrol, instil, distil, enthral, skilful and wilful, while American English writes fulfill, enroll, instill, distill, enthrall, skillful and willful. The noun forms follow suit: instalment and enrolment and fulfilment in British and Australian spelling, installment and enrollment and fulfillment in American.

-ce vs -se, and the noun and verb split

British, Australian and Canadian English write several nouns with -ce where American uses -se: defence, offence and pretence (American defense, offense, pretense).

Two of these carry a further trap that even native writers miss, because the noun and the verb are spelled differently. Licence and practice are the nouns; license and practise are the verbs. So a teacher writes a spelling practice sheet (noun) but asks a child to practise spelling (verb), and a driver holds a licence (noun) but is licensed to drive (verb). American English ignores the split and uses license and practice for both the noun and the verb. The memory hook is advice and advise: the one with c is the thing, the one with s is the doing.

The word pairs teachers trip on

Beyond the tidy patterns there is a set of everyday words that simply differ, and several hide a meaning-based split worth teaching explicitly.

• gray (US) and grey (UK, AU, NZ, Canada): the colour word. A greyhound is grey everywhere.
• math (US, Canada) and maths (UK, AU, NZ): the short form of mathematics keeps the s in British and Australian use.
• curb and kerb: in British and Australian English kerb is the stone edge of a road, while curb is the verb meaning to restrain. American and Canadian English use curb for both.
• program and programme: American, Canadian and computing use always write program. British and Australian English write programme for a TV show, an event or a schedule, but program for a computer program.
• check and cheque: British, Australian and Canadian English use cheque for the bank payment and check for the verb (to examine) and the tick. American English uses check for everything.
• story and storey: a storey (plural storeys) is a floor of a building in British and Australian English; a story is a tale. American English uses story for both.
• tire and tyre: the rubber on a wheel is a tyre in British and Australian English, a tire in American and Canadian.
• aluminium and aluminum: British and Australian English say and write aluminium (al-yoo-MIN-ee-um); American and Canadian English use aluminum.
• mould and mold: the fungus and the shaping form are both mould in British and Australian English, mold in American.
• plough and plow: the farm tool is a plough in British and Australian English, a plow in American.
• sceptical and skeptical: British and Australian English write sceptical with a c; American and Canadian English use skeptical.
• cosy and cozy: cosy in British and Australian English, cozy in American.
• pyjamas and pajamas: children wear pyjamas in Britain and Australia, pajamas in America.
• draught and draft: British and Australian English use draught for airflow and drinks (a draughty room) but draft for a first version; American English uses draft for everything.
• enquire and inquire: British and Australian English often use enquire for a casual question and inquire for a formal investigation (an inquiry); American English uses inquire for both.
• judgement and judgment: everyday British and Australian writing prefers judgement with an e, but legal contexts drop it (the judgment of the court); American English always writes judgment.
• ageing and aging: British and Australian English keep the e in ageing; American English writes aging.
• counsellor and woollen double the l in British and Australian English; American English writes counselor and woolen (the same double-L pattern as travelling).
• doughnut and donut: doughnut is the standard spelling everywhere; donut is an American informal variant common in shop names.
• The -ae- and -oe- words simplify to -e- in American English: paediatric, manoeuvre, encyclopaedia, foetus and anaemia become pediatric, maneuver, encyclopedia, fetus and anemia. British and Australian English keep the older spelling, though encyclopedia is now widely accepted.

Past tenses: -ed vs -t

British and Australian English often use a -t ending on the past tense of some verbs where American English uses -ed: learnt, spelt, dreamt, burnt, leapt, spoilt and knelt. Both forms are understood everywhere, but the -t form reads as natural in Australian classrooms and the -ed form in American ones.

One more for reading aloud: the past participle of get is gotten in American English (she had gotten better) but got in British and Australian English (she had got better). Forgotten is the same everywhere.

The Canadian middle ground

Canada is not simply British or American; it borrows from both, which is why it needs its own note. Canadian English keeps the British -our and -re endings (colour, favour, centre, metre, theatre) and the British -ce nouns (defence, licence), and it uses cheque and grey. But it takes the American -ize and -yze (organize, analyze) and, tellingly for a maths worksheet, it says math, not maths. Canadians also write tire and curb like Americans.

That mix is why a site that only offers US or UK spelling can never be perfect for Canada. On SproutSheets we keep Canada on American-style spelling because the maths word and the -ize endings matter most on a worksheet, and we note the tradeoff openly rather than pretend one setting fits every reader.

At a glance

How SproutSheets keeps it consistent

You should never have to fix spelling by hand. Set your country once with the picker in the header and every worksheet you generate follows it: colour and metre and maths for Australia, the UK and New Zealand; color and meter and math for the United States and Canada. The on-worksheet English toggle lets you switch a single sheet too, which is handy for a mixed class or an EAL lesson comparing the variants.

Answer keys are unaffected because the meaning never changes, only the surface spelling. Print a spelling list, a comprehension passage or a word-problem set and it will read as though it were written for your students, not for someone else's.