British to American Spelling Converter
Paste your text to switch between British and American spelling in one step. About 3,000 word forms are covered, from colour and organise to travelled, defence and paediatric, and every change is highlighted so you can check it.
Last updated:
highlighted = changed spelling. Hover to see the original; click a word to keep its original spelling everywhere in the text.
Changes
How to use the British to American Spelling Converter
- Choose the direction: British → American or American → British.
- Paste or type your text in the left box. The converted version appears on the right as you type.
- Review the highlighted words. Hover to see the original, click a word to keep the original spelling.
- Check the list of changes below the result to see every replacement at a glance.
- Copy the result or download it as a .txt file.
British vs American spelling rules
| Pattern | British | American |
|---|---|---|
| -our / -or | colour, favour, behaviour, neighbour | color, favor, behavior, neighbor |
| -ise / -ize | organise, realise, apologise, organisation | organize, realize, apologize, organization |
| -yse / -yze | analyse, paralyse, catalyse | analyze, paralyze, catalyze |
| -re / -er | centre, theatre, fibre, metre, litre | center, theater, fiber, meter, liter |
| -ence / -ense | defence, offence, pretence, licence (noun) | defense, offense, pretense, license |
| Doubled L | travelled, cancelling, modeller, jewellery | traveled, canceling, modeler, jewelry |
| Single L | fulfil, enrol, skilful, instalment | fulfill, enroll, skillful, installment |
| ae / oe | paediatric, anaemia, oestrogen, manoeuvre | pediatric, anemia, estrogen, maneuver |
| -ogue / -og | catalogue, analogue | catalog, analog |
| Other words | grey, tyre, cheque, aluminium, plough, mould, sceptical, judgement, ageing | gray, tire, check, aluminum, plow, mold, skeptical, judgment, aging |
Some rules have exceptions. Words that end in -ise in both varieties, such as advise, exercise, surprise, compromise and televise, are never changed to -ize. Size, prize and seize keep their z in British English. Humorous, laborious, vigorous and glamorous drop the u in both varieties, and honorary stays the same.
One-way words to watch
A few American spellings are also real British words with another meaning, so the converter only changes them in one direction:
- cheque / check: British cheque (bank) becomes check, but check is not turned into cheque.
- tyre / tire, kerb / curb and storey / story: the British spellings only refer to the wheel, the pavement edge and a floor of a building.
- practise / practice and licence / license: in British English the -ce form is the noun and the -se form the verb; American English uses practice and license for both.
- programme / program and metre / meter: British English uses program for computer software and meter for a measuring device.
Plurals such as analyses and paralyses are left alone when converting to American, because they are also the plurals of analysis and paralysis.
Frequently asked questions
What are the main differences between British and American spelling?
The most common patterns are -our vs -or (colour, color), -ise vs -ize (organise, organize), -re vs -er (centre, center), -ence vs -ense (defence, defense), a doubled L before endings in British English (travelled, traveled) and ae or oe in medical and scientific words (paediatric, pediatric; oestrogen, estrogen). There are also single-word differences such as grey/gray, tyre/tire and aluminium/aluminum.
Is -ize wrong in British English?
No. Oxford spelling, used by Oxford University Press and many international organisations, uses -ize (organize) with otherwise British spelling. Most UK newspapers and schools use -ise. When converting to British, tick Keep -ize endings if you follow Oxford style.
Why were some words like check, tire or practice not changed to British?
These words are correct in British English too, with a different meaning: check is a verb, tire means to get tired, practice is the British noun and meter is a measuring device. The converter only turns cheque, tyre, practise and metre into American spelling, never the other way round, to avoid wrong changes.
Will it change names like Earl Grey or Tyre?
It can, because it works word by word without knowing the meaning of the sentence. Proper names that look like British spellings, such as Grey or Tyre, may be changed. Click the highlighted word in the result to restore the original.
Does it change vocabulary such as lorry to truck?
No. It changes spelling only, so the words stay the same but are spelled the American or British way. Different vocabulary (lorry/truck, flat/apartment, autumn/fall) and grammar differences are left as written.
Is my text uploaded anywhere?
No. The word list is built into the page and the conversion runs entirely in your browser, so your text never leaves your device.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.