Most differences between American and British spelling follow a handful of patterns, many dating from Noah Webster’s reforms in his dictionaries of the early 1800s.
The main patterns
| Pattern | American | British | Notes |
|---|---|---|---|
| -or / -our | color, honor, favorite | colour, honour, favourite | glamour is common in both; honorary and humorous are the same in both |
| -er / -re | center, theater, fiber | centre, theatre, fibre | meter (device) is the same in both; metre is the British unit |
| -ize / -ise | organize, realize | organise, realise | -ize is also correct British (Oxford spelling); advertise, compromise, surprise are -ise everywhere |
| -yze / -yse | analyze, paralyze | analyse, paralyse | no -yze in British |
| -og / -ogue | catalog, analog | catalogue, analogue | dialog box is common in computing everywhere |
| -ense / -ence | defense, offense, license (noun) | defence, offence, licence (noun) | British: license is the verb, licence the noun |
| doubled L | traveled, canceled, counselor | travelled, cancelled, counsellor | British doubles the L before suffixes |
| single L | fulfill, enrollment, skillful | fulfil, enrolment, skilful | the reverse pattern |
| ae / oe | pediatric, anemia, maneuver | paediatric, anaemia, manoeuvre | encyclopedia is standard in both |
Words with no pattern
aluminum / aluminium · gray / grey · tire / tyre · plow / plough · mold / mould · cozy / cosy · pajamas / pyjamas · skeptic / sceptic · check / cheque (bank) · program / programme (except computer program in British) · curb / kerb (road edge) · draft / draught (air, beer)
Several of these are traps: tire is also a British verb (to become tired), check and draft have meanings shared by both varieties. Automatic converters should flag them for review rather than change them blindly.
Oxford spelling
Oxford University Press, Nature, many international organisations and the UN use British spelling with -ize (organize, realize) while keeping colour, centre and travelled. It is fully standard British English.
Australian, Canadian and Indian English
- Australian follows British spelling, with -ise preferred.
- Canadian mixes: British -our and -re (colour, centre), American -ize (organize) and often American tire and curb.
- Indian English generally follows British spelling.
Staying consistent
The real mistake isn’t choosing a variety, it’s mixing them. Set your word processor’s language, then check finished text with the Consistency Checker, which reports US and UK forms used side by side. To switch a whole text, use the US ↔ UK Spelling Converter, which handles every inflected form and leaves ambiguous words for you to decide.
Sources
- Webster, N. (1828). An American Dictionary of the English Language.
- New Oxford Style Manual (Oxford University Press), Oxford spelling.
- Peters, P. (2004). The Cambridge Guide to English Usage.