British ↔ American English converter

1. Paste or type your copy into the text box.
2. Choose a direction — British → American or American → British — with the toggle.
3. Press Convert. Every changed word is highlighted in the output.
4. Read the highlights back, then use Copy to drop the converted text straight into your CMS.

The converter runs entirely in your browser. Nothing you paste is uploaded, stored or sent to a server, so it is safe to use on embargoed or unpublished copy.

Most of the gap between the two varieties is patterned rather than random, which is why a dictionary handles it well:

• -ise / -ize — organise → organize, realise → realize, and the matching nouns organisation → organization.
• -our / -or — colour → color, honour → honor, neighbour → neighbor, favourite → favorite.
• -re / -er — centre → center, theatre → theater, litre → liter, fibre → fiber.
• -ogue / -og — catalogue → catalog, dialogue → dialog, analogue → analog.
• -yse / -yze — analyse → analyze, paralyse → paralyze.
• Doubled consonants — travelled → traveled, cancelled → canceled, modelling → modeling, marvellous → marvelous.
• -ce / -se — defence → defense, offence → offense, practise → practice.
• ae / oe ligatures — anaemia → anemia, paediatric → pediatric, foetus → fetus.
• Vocabulary — pavement → sidewalk, autumn → fall, holiday → vacation, mobile → cellphone, lorry → truck, petrol → gasoline.

This is a curated common set, not a full translator. It converts spelling and frequent vocabulary swaps; it does not rewrite grammar, idiom, punctuation conventions, currency, measurements or date formats, and it cannot judge context.

A handful of words are genuinely ambiguous — boot, flat, chips, lift, queue — so those swaps run British to American only, and proper nouns, quotations and brand names should always be checked by hand. Treat the output as a fast first pass for a sub-editor, not a replacement for one.