British vs American Spelling: The Complete Guide (And Which One to Use)
December 30th, 2025
British vs American Spelling: The Complete Guide (And Which One to Use)
If you've ever hesitated over colour versus color, wondered whether to write organise or organize, or been confused about travelled versus traveled, you're not alone. The differences between British and American spelling trip up millions of writers every day - native speakers, ESL learners, professionals, students, and anyone who writes for an international audience. And while these differences might seem minor, they can create real confusion in academic writing, professional communication, and standardized tests like IELTS and TOEFL.
The good news is that neither British nor American spelling is "more correct" than the other. They're both perfectly valid systems with their own histories, rules, and patterns. The key isn't choosing the "right" one forever - it's understanding the differences, choosing appropriately for your context, and being consistent within any single piece of writing. Once you grasp the core patterns, the whole system becomes manageable, and you'll stop second-guessing yourself every time you write center or centre.
This guide covers everything you need to know: the historical origins of these spelling differences, the major pattern categories, a comprehensive reference table, practical advice for exams and professional writing, and strategies for building consistency into your writing habits.
Quick Answer: Which One Should You Use?
- Writing for a US audience, US company, or TOEFL: Use American spelling (color, center, organize).
- Writing for a UK audience, UK company, or most UK/Australian institutions: Use British spelling (colour, centre, organise).
- Writing for an international audience: Either is fine - pick one and stay consistent within the document.
Why Do British and American Spelling Differ in the First Place?
The split between British and American spelling didn't happen by accident. It was largely the result of deliberate reform efforts in early America, combined with the natural evolution of written English over centuries.
When English colonists arrived in America, they brought British spelling with them. For the first century or so, spelling on both sides of the Atlantic was largely the same - and both were more chaotic than today. English spelling wasn't standardized until dictionaries became widespread, and even then, variation was common.
The major divergence came in the early 1800s, when American lexicographer Noah Webster published his American Dictionary of the English Language (1828). Webster believed that American English should reflect American identity, and he deliberately simplified many spellings. He dropped the "u" from words like colour and honour, changed -re endings to -er in words like centre, and standardized -ize spellings instead of -ise. His goal was to make spelling more logical, more phonetic, and distinctly American.
Meanwhile, British English retained the older French and Latin-influenced spellings that had been standard for centuries. Samuel Johnson's Dictionary of the English Language (1755) had already established many of these conventions in Britain, and they remained largely unchanged.
The result is two parallel spelling systems that are both internally consistent, both "correct," and both used by hundreds of millions of people worldwide. Understanding this history helps explain why the differences exist - and why neither system is inherently better.
The Major Categories of British vs American Spelling Differences
The differences between British and American spelling aren't random. They follow predictable patterns that, once learned, apply across hundreds of words. Here are the main categories:
1. The -our / -or Pattern
One of the most recognizable differences is the British -our ending versus the American -or ending. This pattern appears in dozens of common words:
| British | American |
|---|---|
| colour | color |
| favour | favor |
| honour | honor |
| labour | labor |
| behaviour | behavior |
| neighbour | neighbor |
| humour | humor |
| flavour | flavor |
| harbour | harbor |
| rumour | rumor |
The British spellings come from Old French, where the -our ending was standard. American spelling dropped the "u" as part of Webster's simplification efforts.
Important note: Derived forms can vary, especially in technical or academic writing. In American English, the "u" is usually dropped consistently (color, coloration). In British English, you’ll often see the "u" kept (colour, colouration), but some derived forms may appear without it depending on the dictionary, publisher, and field. When in doubt, follow your institution/style guide - and keep your choices consistent within the same document.
2. The -ise / -ize Pattern
This is one of the trickiest patterns because it's not as clear-cut as people think. American English consistently uses -ize endings: organize, realize, recognize, apologize, criticize. British English traditionally accepts both -ise and -ize, though -ise is more common in everyday British writing.
| British (common) | American |
|---|---|
| organise | organize |
| realise | realize |
| recognise | recognize |
| apologise | apologize |
| criticise | criticize |
| emphasise | emphasize |
| analyse | analyze |
| paralyse | paralyze |
However, some words always end in -ise regardless of variety because the -ise is part of the root, not a suffix. These include: advertise, advise, compromise, despise, devise, disguise, exercise, improvise, revise, supervise, surprise, televise. Don't change these to -ize - they're spelled the same in both systems.
For IELTS and TOEFL: Both -ise and -ize are accepted in IELTS (which uses British English as default), but consistency is essential. If you write organise in one paragraph and realize in the next, that's a problem. American -ize is standard for TOEFL.
3. The -re / -er Pattern
Another highly visible pattern is the British -re ending versus the American -er ending:
| British | American |
|---|---|
| centre | center |
| metre | meter |
| theatre | theater |
| litre | liter |
| fibre | fiber |
| sabre | saber |
| calibre | caliber |
| sombre | somber |
This pattern comes from French influence on British English. American English reversed the letters to match pronunciation more closely.
Exception: Some words use -er in both varieties, especially when the ending isn't pronounced the same way. Acre, massacre, and mediocre are spelled identically in both systems.
4. The Double Consonant Pattern
When adding suffixes like -ed, -ing, or -er to verbs, British and American English sometimes double consonants differently:
| British | American |
|---|---|
| travelled | traveled |
| travelling | traveling |
| cancelled | canceled |
| cancelling | canceling |
| modelled | modeled |
| labelled | labeled |
| jewellery | jewelry |
| marvellous | marvelous |
British English tends to double the final "l" before adding a suffix, while American English often keeps it single. This is one of the most common sources of spelling inconsistency for writers who aren't sure which system they're using.
5. The -ogue / -og Pattern
American English sometimes shortens -ogue endings to -og:
| British | American |
|---|---|
| catalogue | catalog |
| dialogue | dialog |
| analogue | analog |
| prologue | prolog |
However, in practice, many Americans still use the -ogue spellings, especially in formal writing. Catalog is standard in American English, but dialogue is common in both.
6. The -ence / -ense Pattern
A few words differ in their -ence/-ense endings:
| British | American |
|---|---|
| defence | defense |
| offence | offense |
| licence (noun) | license |
| pretence | pretense |
British English uses licence as a noun and license as a verb (like practice/practise), while American English uses license for both.
7. Other Individual Word Differences
Some words don't fit neatly into patterns and simply need to be memorized:
| British | American |
|---|---|
| aeroplane | airplane |
| aluminium | aluminum |
| cheque (bank) | check |
| grey | gray |
| kerb (road edge) | curb |
| mould | mold |
| plough | plow |
| programme (TV, etc.) | program |
| pyjamas | pajamas |
| sceptical | skeptical |
| tyre | tire |
| draught (beer, air) | draft |
These variations are fewer in number but appear frequently in everyday writing.
Which Spelling System Should You Use?
The answer depends entirely on your context. Here's a practical guide:
For IELTS Candidates
IELTS is a British exam, and British English is the default. However, American spellings are accepted as long as you're consistent. The key word is consistent. If you write color in your Task 1 and colour in your Task 2, examiners may view this as a spelling error. Pick one system and stick with it throughout the entire test.
For more on IELTS spelling strategies, see: The Hidden Reason IELTS Candidates Lose a Whole Band: Spelling
Also helpful: 10 IELTS Spelling Mistakes Every Candidate Makes (And How to Fix Them Fast)
For TOEFL Candidates
TOEFL is an American exam, so American spellings are standard. While British spellings aren't usually penalized, using American spelling removes any doubt and ensures consistency with the test materials you've been studying.
For Academic Writing
Follow the convention of your institution, journal, or field. British universities generally expect British spelling. American universities expect American spelling. If you're submitting to an international journal, check their style guide. When in doubt, ask.
For Professional and Business Writing
Match your audience. If you're writing for a UK-based company, use British spelling. If you're in a US company, use American spelling. For international audiences, either system works - just be consistent.
For ESL Learners Generally
Choose the system that matches your primary exposure or future goals. If you're planning to study in the UK, Australia, or countries that use British English, lean British. If you're targeting the US or Canada, lean American. Neither choice is wrong, but consistency makes you look more polished.
How to Build Spelling Consistency (Practical Strategies)
Knowing the patterns isn't enough - you need to build consistency into your writing habits. Here's how:
1. Set Your Default and Commit
Choose one spelling system as your default. This doesn't mean you'll never use the other - it means you have a clear baseline. When you're unsure, you default to your chosen system. This removes hesitation and makes writing faster.
2. Configure Your Tools
Set your word processor's spell-check to your chosen variety:
- In Microsoft Word: File → Options → Language → Set your proofing language to "English (UK)" or "English (US)"
- In Google Docs: Tools → Spelling and Grammar → Spelling Settings → Choose your variety
- On your phone: Keyboard settings → Language → Choose your English variant
When your tools match your chosen system, they'll catch inconsistencies automatically.
3. Create a Personal Reference List
Write down the 20–30 words you use most frequently that differ between systems. Keep this list visible when you write. Over time, the correct spellings will become automatic.
4. Do a Consistency Check Before Submitting
Before submitting any important document (essay, email, report, application), search for common variant words:
- Search for "ise" and "ize" - are they consistent?
- Search for "our" and "or" (word endings) - any mixing?
- Search for "re" and "er" (in words like centre/center) - all the same?
This 30-second check catches most inconsistencies.
5. Practice with Focus
If you're preparing for an exam or working to improve your spelling generally, practice with words from your chosen system. Don't mix systems in your practice lists. Consistency in practice builds consistency in performance.
For a structured daily routine: The 10-Minute Daily Spelling Practice Routine
Quick Reference Table: The Most Common Differences
Here's a comprehensive table of the most frequently used words that differ between systems:
| British | American | Category |
|---|---|---|
| colour | color | -our/-or |
| favour | favor | -our/-or |
| honour | honor | -our/-or |
| labour | labor | -our/-or |
| behaviour | behavior | -our/-or |
| neighbour | neighbor | -our/-or |
| organise | organize | -ise/-ize |
| realise | realize | -ise/-ize |
| recognise | recognize | -ise/-ize |
| apologise | apologize | -ise/-ize |
| analyse | analyze | -yse/-yze |
| paralyse | paralyze | -yse/-yze |
| centre | center | -re/-er |
| metre | meter | -re/-er |
| theatre | theater | -re/-er |
| litre | liter | -re/-er |
| fibre | fiber | -re/-er |
| travelled | traveled | double consonant |
| cancelled | canceled | double consonant |
| modelled | modeled | double consonant |
| jewellery | jewelry | double consonant |
| defence | defense | -ence/-ense |
| offence | offense | -ence/-ense |
| licence (n.) | license | -ence/-ense |
| catalogue | catalog | -ogue/-og |
| dialogue | dialog | -ogue/-og |
| grey | gray | individual |
| cheque | check | individual |
| programme | program | individual |
| aeroplane | airplane | individual |
| aluminium | aluminum | individual |
| sceptical | skeptical | individual |
| draught | draft | individual |
| mould | mold | individual |
| plough | plow | individual |
| pyjamas | pajamas | individual |
| tyre | tire | individual |
| kerb | curb | individual |
Print this table or save it as a reference. Over time, you'll internalize the patterns and won't need to check.
Common Mistakes and How to Avoid Them
Mixing Systems in the Same Document
The most common error isn't using the "wrong" system - it's mixing systems. Writing organization in one paragraph and organisation in the next makes your writing look inconsistent and suggests you're uncertain about spelling. Always choose one and stick with it.
Hypercorrection
Sometimes learners "overcorrect" by applying British spelling where it doesn't apply. For example, writing practise when you mean the noun (British uses practice for the noun). Or adding a "u" to words that don't have one in either system. Trust the patterns, and when in doubt, check.
Forgetting About Suffixes
Remember that suffixes can change spelling behavior. British colour becomes coloration (no "u"). British honour becomes honorary. Both systems use organization (noun) even when the verb differs. Pay attention to how words change when suffixes are added.
Assuming One System Is "More Correct"
Neither British nor American spelling is superior. They're both valid, established systems used by millions of educated writers. The goal is appropriateness and consistency, not correctness in some absolute sense.
FAQ: British vs American Spelling
"My school taught British spelling, but I watch American shows. Am I going to mix them up?"
This is common for ESL learners, especially in countries with British colonial history but heavy American media influence (India, Singapore, Malaysia, the Philippines, many African countries). The solution is awareness: know which words differ, choose your system deliberately, and check your work. If you're preparing for a specific exam, practice with that system exclusively.
"Does IELTS penalize American spelling?"
No. IELTS accepts both British and American spellings. What matters is consistency. If you use American spelling throughout, that's fine. If you mix, that's a problem.
"I'm writing for an international audience. Which should I use?"
Either works. What matters most is consistency and clarity. Many international organizations use American spelling because it's more widely understood globally, but British spelling is equally acceptable. Choose based on your audience or your organization's style guide.
"Are there any words spelled the same in both systems?"
Yes, the vast majority of English words are spelled identically in both British and American English. The differences, while noticeable, affect only a small percentage of the vocabulary. Most of your writing will look the same regardless of which system you use.
Putting It All Together: Your Action Plan
Here's what to do with everything you've learned:
Step 1: Choose your default system based on your goals (exams, work, audience).
Step 2: Learn the five major pattern categories (-our/-or, -ise/-ize, -re/-er, double consonants, -ence/-ense).
Step 3: Create a personal list of the 20–30 words you use most often from the reference table.
Step 4: Configure your digital tools to match your chosen system.
Step 5: Practice writing with consistency. When you review your work, check for variant spellings.
Step 6: Before any important submission, do a quick search for common differences.
Over time, your chosen system will become automatic. You'll stop hesitating, stop second-guessing, and write with confidence.
Related Reading on Spelling.School
For ESL learners building a complete spelling system:
For understanding spelling patterns:
For exam preparation:
- The Hidden Reason IELTS Candidates Lose a Whole Band: Spelling
- How to Study Spelling for IELTS (And Why It Matters More Than Grammar)
For daily practice:
- The 10-Minute Daily Spelling Practice Routine
- The Science of Spelling: How Spaced Repetition Boosts Memory
More guides you may like:
-
Silent Letters in English: A Complete Guide to Words You Can't Sound Out
-
The Most Common English Spelling Mistakes Spanish Speakers Make (And How to Fix Them)
Conclusion: Consistency Is the Real Goal
British and American spelling differences can feel overwhelming when you first encounter them, but they're surprisingly manageable once you understand the underlying patterns. The -our/-or, -ise/-ize, -re/-er, and double consonant patterns cover the vast majority of differences you'll encounter. Learn these patterns, choose your system, and commit to consistency.
Remember: no one expects you to know both systems perfectly. What matters is that you write with intention, that you're aware of the variations, and that you don't mix systems within the same piece of writing. Whether you choose colour or color, organise or organize, centre or center - the key is making a choice and sticking with it.
English spelling has room for both traditions. Once you pick your path, the writing becomes easier, faster, and more confident. And that's what spelling mastery is really about.
