British to American Spelling Converter
Paste text in British or American English and convert it to the other: colour to color, organise to organize, centre to center, travelled to traveled. Every change is highlighted and listed by pattern, words whose spelling depends on their meaning are flagged for you to decide, and capitalized names are left alone.
Paste your text to convert it.
How to Use the British to American Spelling Converter
- Choose the direction. British → American or American → British. Converting to British, you can switch on Oxford spelling to keep -ize endings.
- Paste your text. The converted version appears below as you type, with every changed word highlighted.
- Review the flags and the change list. Words whose spelling depends on their meaning are marked for you to decide. Tick Keep original beside any word that should not change — a quotation, a title, a name.
- Copy or download the result. Copy the converted text to your clipboard, or save it as a .txt file.
The Spelling Patterns It Converts
| Pattern | British | American | Note |
|---|---|---|---|
| -our / -or | colour, behaviour, favourite | color, behavior, favorite | Derived words vary: humour becomes humor, but humorous is the same in both. |
| -re / -er | centre, fibre, litre, theatre | center, fiber, liter, theater | Centred becomes centered. Diameter and parameter never change. |
| -ise / -ize | organise, realise, organisation | organize, realize, organization | Advertise, compromise, exercise, revise, and surprise end in -ise everywhere. |
| -yse / -yze | analyse, paralyse | analyze, paralyze | Oxford spelling keeps -yse. |
| -ogue / -og | catalogue, analogue | catalog, analog | Dialogue, monologue, and prologue keep -ue in American English too. |
| Doubled l | travelled, labelling, counsellor | traveled, labeling, counselor | Only when the last syllable is unstressed: controlled and compelled are the same in both. |
| -l / -ll | enrol, fulfil, skilful, instalment | enroll, fulfill, skillful, installment | Enrolled and fulfilled are spelled the same in both. |
| -ce / -se | defence, offence, licence | defense, offense, license | British writes the nouns licence and practice with -ce, the verbs license and practise with -se; see below. |
| ae, oe / e | anaemia, oestrogen, paediatric, manoeuvre | anemia, estrogen, pediatric, maneuver | Archaeology and aesthetic are common in American English, so they convert toward British only. |
| Other | grey, mould, plough, sceptical, aluminium | gray, mold, plow, skeptical, aluminum | Tyre, cheque, kerb, and storey convert toward American only. |
The converter works from a curated list of more than 1,500 word pairs, written out from these patterns with every derived form listed by hand rather than produced by a rule. That is why humorous, vigorous, and laborious are left alone, and why a word that ends in -ise in every variety never changes. The pairs follow the spellings Merriam-Webster gives as standard American English and the Oxford dictionaries give as standard British English. Prefixed forms such as reorganise, unfavourable, and multicoloured convert through their root, and capitalization is kept: Colour becomes Color, COLOUR becomes COLOR.
Oxford Spelling
Oxford spelling, named after Oxford University Press, combines British spellings with the -ize ending: colour and centre, but organize and realize. It is the house style of the Press and is common in academic and international publishing. The -yse in analyse is part of the word's root rather than the -ize suffix, so Oxford spelling still writes analyse and paralyse. With the option on, the converter turns color into colour and analyzed into analysed but leaves organized as it is.
Words That Depend on Meaning
Some words cannot be converted by spelling alone. British English writes practice and licence for the nouns but practise and license for the verbs; American English uses practice and license for both. So British practise always becomes practice, while American practice could be either. The converter flags such words instead of guessing, with a note on how to choose. The same goes for meter (a unit or an instrument), program (software or a schedule), tire and curb (nouns or verbs), and, converting to American, analyses, which is either a verb or the plural of analysis.
A few British words convert in one direction only. A cheque is always a check in American English, but an American check is seldom a cheque; tyre, kerb, storey, and programme work the same way. They change from British to American and are left alone in the other direction.
Worked Example
Choose Try a sample with British → American selected. The converter makes 14 changes across nine patterns — centre to center, analysed to analyzed, travellers to travelers, programme’s to program’s, manoeuvre to maneuver, among others. It leaves Labour Party untouched as a name and flags analyses, which is a verb in that sentence but could be a plural noun elsewhere.
- Names and titles. Capitalized words inside a sentence are left unchanged by default, because they are usually names: the Labour Party, Pearl Harbor, the Centers for Disease Control. A capitalized ordinary word in a title-case heading is left too, and listed so you can change it by hand.
- Quotations. A quotation keeps its original spelling. Tick Keep original for the words involved, or convert only your own prose.
- Vocabulary is not spelling. Only spelling changes. Word choices that differ between the varieties — autumn and fall, pavement and sidewalk, whilst and while — are left as written.
- Unknown words pass through. A word that is not in the list stays exactly as you typed it rather than being guessed at.
Frequently Asked Questions
- Is -ise or -ize correct in British English?
- Both. The -ise ending is more common in British publishing, while -ize — Oxford spelling — is the older form and is used by Oxford University Press and many academic publishers. Pick one and use it consistently. Words such as analyse are spelled -yse in British English either way.
- Which spelling should I use in an academic paper?
- The one your publisher, journal, or institution expects. APA Style takes its spellings from Merriam-Webster, so APA papers use American spelling; many universities outside the United States accept either variety as long as it is used consistently. When you submit to a journal, check its style guide.
- Does it change words inside quotations?
- Yes, if they are in the list — the converter cannot tell your words from a source's. Quotations should keep their original spelling, so tick Keep original for the affected words or convert your own paragraphs separately.
- Why wasn't practice or license converted?
- In British English their spelling depends on the part of speech: practice and licence are nouns, practise and license are verbs. American English uses one spelling for both, so the converter flags the word and lets you decide instead of guessing.
- Does it convert vocabulary such as lorry and truck?
- No. It changes spelling only. Differences in vocabulary, idiom, punctuation, and date format between British and American English are left for you to handle.
- How complete is the word list?
- It holds more than 1,500 pairs covering the regular patterns, the common academic -ise verbs and their -isation nouns, and the medical ae and oe spellings. A word missing from the list is left unchanged rather than altered by a rule, so proofread the result once.
- Is my text uploaded anywhere?
- No. The conversion runs entirely in your browser; your text is never sent to a server or stored.