British vs American spelling
The patterns, the exceptions and a converter. Paste American text, tick Britishify, and see exactly what changes.
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The patterns, in one minute
Most differences fall into a handful of rules. Learn the rules and you can predict most words.
- American -or becomes British -our: color, colour.
- American -er becomes -re after certain consonants: center, centre.
- American -ize is usually -ise in British: realize, realise. (Some British publishers use -ize. Both are acceptable; -ise is the common default.)
- American noun -se becomes -ce: defense, defence. The verb often keeps -se in both (to license, a licence).
- British doubles the final L when adding an ending: traveling, travelling; canceled, cancelled.
Reference table
-or to -our
| American | British |
|---|---|
| color | colour |
| honor | honour |
| neighbor | neighbour |
| flavor | flavour |
| humor | humour |
| labor | labour |
| behavior | behaviour |
| harbor | harbour |
| rumor | rumour |
-er to -re
| American | British |
|---|---|
| center | centre |
| theater | theatre |
| meter | metre |
| liter | litre |
| fiber | fibre |
| maneuver | manoeuvre |
-ize to -ise
| American | British |
|---|---|
| realize | realise |
| organize | organise |
| recognize | recognise |
| apologize | apologise |
| criticize | criticise |
| civilization | civilisation |
| organization | organisation |
| realization | realisation |
-se to -ce, and doubled letters
| American | British |
|---|---|
| defense | defence |
| offense | offence |
| license | licence |
| pretense | pretence |
| traveling | travelling |
| traveled | travelled |
| canceled | cancelled |
| canceling | cancelling |
| modeling | modelling |
-og to -ogue, and the odd ones
| American | British |
|---|---|
| catalog | catalogue |
| dialog | dialogue |
| analog | analogue |
| gray | grey |
| jewelry | jewellery |
| skeptical | sceptical |
| aluminum | aluminium |
| tire | tyre |
| program | programme |
| check | cheque |
| curb | kerb |
| plow | plough |
| mom | mum |
| pajamas | pyjamas |
| donut | doughnut |
| sulfur | sulphur |
| maneuver | manoeuvre |
| esthetic | aesthetic |
| fetus | foetus |
Words that change, not just letters
Spelling gets all the attention, but vocabulary is what actually makes a script sound American to a British ear. Here are the swaps the tool knows about. A few ambiguous ones (like “chips” and “pants”) are deliberately left out of the automatic swap, because the meaning depends on context.
| American | British |
|---|---|
| apartment | flat |
| elevator | lift |
| truck | lorry |
| cookie | biscuit |
| cookies | biscuits |
| candy | sweets |
| fries | chips |
| sidewalk | pavement |
| soccer | football |
| vacation | holiday |
| diaper | nappy |
| trash | rubbish |
| garbage | rubbish |
| flashlight | torch |
| eggplant | aubergine |
| zucchini | courgette |
| cilantro | coriander |
| sneakers | trainers |
| sweater | jumper |
| faucet | tap |
| stroller | pushchair |
| movie | film |
| movies | films |
| subway | underground |
| highway | motorway |
| parking lot | car park |
| restroom | toilet |
| drugstore | chemist |
| cell phone | mobile phone |
| awesome | brilliant |
| guys | lads |
| buddy | mate |
| dude | mate |
Using the converter
The box at the top has the Britishify switch ticked already. Press Generate and you will see the converted text, with every changed word listed, and hear it read in the voice you picked. It works in two stages: a word list for the sure things, then a small AI model to catch anything else. The model is deliberately small and cheap, so it can miss things and occasionally over-edit. That is why the changes are shown rather than hidden.
Spelling alone does not change how a voice sounds, but the vocabulary swaps do. If you plan to use the result as a script for voice-over, remember that your audience hears the words, not the spelling.
For help with phrasing beyond spelling, see the slang guide.
Questions people ask
What is the difference between British and American spelling?
A small, regular set of patterns: -our versus -or (colour/color), -re versus -er (centre/center), -ise versus -ize (organise/organize), -ce versus -se for nouns (defence/defense), and doubled consonants (travelling/traveling). Then a few one-offs such as grey/gray and tyre/tire.
Is -ize always American?
No. Oxford University Press and some British publishers use -ize (organize), while most British writers use -ise. -ise is the safer choice for a general British audience. -yse (analyse) is British regardless.
Does the voice read British and American spellings differently?
Not for pure spelling changes: colour and color sound the same. The difference shows up in vocabulary, where “flat”, “lift” and “boot” sound right in a British voice. So the tool changes both.
How accurate is the Britishify tool?
The word-list pass is exact. A small language model then looks for leftovers, which is helpful but not perfect, so the tool shows you every change. Always read the output. A few words, like “chips” or “pants”, mean something different in each country and we leave those alone.
Which words are different in meaning, not just spelling?
Pants (underwear in the UK), chips (hot, thick fried potatoes), biscuit (a cookie, or a hard one), football (the game Americans call soccer), and pavement (the sidewalk). Context decides, so these need a human.
Keep going
- British accent generator
The main tool: seven voices, Britishify toggle, free clips. - British slang phrases
A guide you can paste straight into the generator. - British accent text to speech
How British TTS works and how to write text that reads naturally.