British ↔ American spelling converter
Paste a draft, pick a direction, and every variant spelling is switched in one pass. Around 160 pairs, case preserved, nothing sent to a server.
The dictionary behind this tool is published as a reference: the full list of 166 British and American differences, grouped into spelling, word choice and the forms both markets accept.
Result
Everything runs in this browser tab. Nothing is uploaded, stored or logged.
What it changes, and what it leaves alone
It swaps spelling variants only: words where British and American English disagree on letters, not on meaning. Style, punctuation and terminology stay exactly as you wrote them. That is deliberate — a converter that also rewrites your voice is a converter you cannot trust in a client document.
Case is preserved, so Favourite becomes Favorite and not favorite. Possessives and plurals are handled because the match is on the whole word.
Two things to watch
- licence / license — in British English the noun is licence and the verb is license. The tool assumes the noun. Check any sentence that uses it as a verb.
- practice / practise — same split in British English: noun practice, verb practise. The tool converts practise to practice, which is correct for American English but needs a read-through when going the other way.
- Proper nouns — a company called Honour & Co will become Honor & Co. Convert first, then restore names.
Which way should you go?
Pick the variant of your main audience and use it everywhere, including the pages nobody reads closely. Mixed spelling is the detail that makes a UK buyer assume the company is not really British, and it is the first thing an editor marks up.
The full reasoning, including the exceptions that genuinely are exceptions, is in British vs American English in business writing. If you need the decision written down for a team, the house style guide shows what to record.
Paste the result into the readability checker next — spelling consistency and readability are the two cheapest fixes on any page.
Want someone else to do this pass?
Every article we deliver is checked for spelling variant, readability and house style before it is sent.