British ↔ American English Converter

Switch a text between British and American spelling in one step: colour and color, organise and organize, centre and center, travelled and traveled, defence and defense, catalogue and catalog, grey and gray, aluminium and aluminum. Use it before sending a CV, an essay or a website to readers on the other side of the Atlantic. An option keeps Oxford -ize spellings, and another swaps everyday words such as lorry and truck.

How to use this tool

1. Paste your text.
2. Choose British → American or American → British.
3. For British output, tick the Oxford option if your publisher prefers organize and realize.
4. Optionally swap everyday vocabulary, then copy the result and check the table of changes.

Formula

Word families: -our ↔ -or, -ise ↔ -ize, -yse ↔ -yze, -re ↔ -er, -ll- ↔ -l-, -ogue ↔ -og, ae/oe ↔ e, -ce ↔ -se, plus a list of single words

Families are generated with their endings, so colour gives coloured, colourful and colourless, and organise gives organised, organising and organisation. Only verbs that take -ize in American English are in the -ise list, so advertise, surprise, compromise and exercise never change. A word keeps its capitals (COLOUR → COLOR) and possessive (neighbour’s → neighbor’s). Words whose spelling depends on meaning, such as check/cheque, tire/tyre, story/storey, program/programme and meter/metre, change only from British to American, because an American text does not say which meaning is meant.

Example

British → American turns the sample into “Our neighbor traveled to the theater center to organize a colorful program. Her favorite catalog analyses the defense of the gray harbor.”: 12 words change. “Analyses” is left alone because it is also the plural of “analysis”. Going the other way restores the British spelling, except that program stays program, because British English uses that spelling for computer programs.