If you’ve ever paused mid-sentence and wondered whether it’s “realise” or “realize,” or whether your British readers will frown at the word “apartment,” you’re not alone. For writers working in a global context—whether they’re writing an academic paper, a professional blog, or even a social media caption—understanding the nuances between British and American English is not only helpful, but essential.

Although British and American English come from the same language family, centuries of evolution, geography, and culture have led to significant differences in vocabulary, spelling, grammar, punctuation, and even writing style. Choosing the right variant is often about more than correctness—it’s about clarity, consistency, and credibility. 

In this guide, we look at the key differences that every writer—academic or non-academic—needs to know and give examples and practical tips on how to stay consistent across your work. 

Spelling differences

Spelling is often the first and most obvious difference between the two versions of English. American English, influenced by 19th-century reformers such as Noah Webster, tends to simplify spelling to more closely match pronunciation. British English, on the other hand, retains many traditional spellings that reflect the French and Latin roots of the language.

Examples

-our vs. -or

• British English: colour, favour, behaviour
• American English: color, favor, behavior

British English retains the “u” from its French origins, while American English simplifies these to prioritise phonetic clarity.

-ise vs. -ize

• British English: organise, realise
• American English: organize, realize

In British English, both -ise and -ize endings are used, though some institutions like Oxford University Press prefer the -ize forms. In American English, -ize is standard.

Centre vs. Center

• British English: centre
• American English: center 

Travelling vs. Traveling

• British English: travelling
• American English: traveling

Catalogue vs. Catalog

• British English: catalogue
• American English: catalog

Licence vs. License

• British English: licence (noun)
• American English: license (noun and verb)

These differences may seem insignificant, but in academic or professional contexts, even small inconsistencies can make your text appear unpolished and unprofessional. That’s why it’s important that you commit to a particular spelling from the start—and stick to it. 

See also: How InstaText helps non-native speakers overcome common writing challenges

Vocabulary differences

Apart from spelling, there are many differences in vocabulary between British and American English. Some are amusing, some are subtle, and some can cause real confusion.

Examples: Everyday terms 

Flat vs. Apartment

• British English: flat
• American English: apartment

Car park vs. Parking lot

• British English: car park
• American English: parking lot

Petrol vs. Gas

• British English: petrol
• American English: gas

Holiday vs. Vacation

• British English: holiday
• American English: vacation

Examples: Academic terminology

Modules vs. Courses

• British English: modules
• American English: courses

Dissertation vs. Thesis (UK)

• British English: dissertation (for undergraduate or master’s level)
• American English: thesis (master’s level)

Thesis vs. Dissertation (US)

• British English: thesis (PhD level)
• American English: dissertation (PhD level)

Using these terms incorrectly can signal to readers that you are unfamiliar with their linguistic and cultural norms. If you are writing for an international audience, you need to be aware of these regional preferences and adapt your choice of words accordingly.

Grammatical differences

Although the grammar rules between the two variants of English are largely similar, there are enough differences to confuse even experienced writers.

Examples

Present perfect tense vs. Simple past

• British English: I’ve just eaten lunch.
• American English: I just ate lunch.

In British English, the present perfect tense is preferred for actions that have recently occurred. In American English, the simple past is more commonly used in these situations.

Gotten vs. Got

• British English: He’s got better at editing.
• American English: He’s gotten better at editing.

American English uses “gotten” as the past participle of “get,” whereas British English typically uses “got” for both past and past participle forms.

Prepositions

• British English: at the weekend, in hospital
• American English: on the weekend, in the hospital

British English uses “at the weekend” and “in hospital,” while American English prefers “on the weekend” and “in the hospital.”

Different to vs. Different from/than

• British English: different to
• American English: different from (or occasionally different than)

British English commonly uses “different to,” while American English generally prefers “different from” or, in some cases, “different than”.

Collective nouns

• British English: The team are winning.
• American English: The team is winning. 

In British English, collective nouns like team, company, or band are often treated as plural. In American English, they are treated as singular.

Punctuation and quotation marks

Punctuation is another area where regional preferences can dramatically shift the tone and look of your writing.

Quotation marks

• British English: Uses single quotation marks for primary quotes and double quotation marks for quotes within quotes.

Example: ‘like this’ (primary quote), ‘He said “hello”’ (quote within a quote).

• American English: Uses double quotation marks for primary quotes and single quotation marks for nested quotes.

Example: “like this” (primary quote), “He said ‘hello’” (quote within a quote).

Placement of punctuation with quotation marks

• British English: Punctuation goes outside the quote unless it’s part of the quoted material.

Example: She called it ‘brilliant’.

• American English: Punctuation is typically placed inside the quotation marks.

Example: She called it “brilliant.”

Oxford comma

• British English: Tends to omit the Oxford comma unless its absence creates ambiguity.

• Without Oxford comma: I’d like to thank my supervisor, the committee members and the editor.
• With Oxford comma: I spoke to the marketing heads, Sarah and Tom.
• With Oxford comma: I spoke to the marketing heads, Sarah, and Tom.

• American English: Widely accepts the use of the Oxford comma, especially in formal writing.

• With Oxford comma: I’d like to thank my supervisor, the committee members, and the editor.

Abbreviations

• British English: Omits periods in titles such as Mr, Dr, and Mrs.

Example: Mr Smith, Dr Johnson, Mrs Taylor

• American English: Includes periods in these titles.

Example: Mr. Smith, Dr. Johnson, Mrs. Taylor

See also: Self-editing: Simple tips to improve your own writing

Formatting and style conventions

Formatting isn’t just about aesthetics. It is essential for making your writing clear and easy to follow, especially in academic contexts.

Date formatting

• British English: Dates are written as 5 November 2025 or 05/11/2025.
• American English: Dates are written as November 5, 2025 or 11/05/2025. 

Time formatting

• British English: Often uses the 24-hour clock (e.g. 14:00).
• American English: Typically uses the 12-hour clock with AM/PM notation (e.g. 2:00 PM). 

Citation styles

• British English: British universities may prefer citation styles such as Harvard, Oxford, or MHRA.
• American English: In the U.S., citation styles like MLA, APA, and Chicago dominate. 

Formatting requirements

• British English: Formatting requirements for papers, such as whether to include a title page or where to place the abstract, may differ.
• American English: American institutions may have different formatting rules, like the order of sections or the inclusion of specific elements.

Even if these stylistic differences are seemingly insignificant, they can have a significant impact. If you submit a paper formatted in APA style to a British journal that uses MHRA style, it may result in rejection or extensive revision requests.

Tone and style

One of the more abstract yet important differences between British and American English lies in tone.

British English: More formal and polite

British English tends to be more formal and reserved in tone, especially in academic and professional contexts. Writers are likely to use expressions that soften their requests and express politeness and respect.

• Example: “Would you mind if…”
• Example: “I was wondering whether you could…”

American English: More direct and conversational

American English is generally more straightforward and conversational. The emphasis is on clarity and efficiency, with less focus on formality. Phrases are often short and to the point.

• Example: “Can you send this by Monday?”
• Example: “Let’s get this done today.”

These differences can impact how your writing is perceived. British readers might find American-style communication too abrupt, while Americans may interpret British writing as overly formal or indirect.

This table summarises the main differences between British and American English and provides examples to help you maintain consistency in your writing.

Category	British English	American English
Spelling differences	-our vs. -or (colour, favour, behaviour)	-or (color, favor, behavior)
	-ise vs. -ize (organise, realise)	-ize (organize, realize)
	Centre	Center
	Travelling	Traveling
	Catalogue	Catalog
	Licence (noun)	License (noun and verb)
Vocabulary differences	Flat, car park, petrol, holiday, modules, dissertation (undergraduate or master’s)	Apartment, parking lot, gas, vacation, courses, thesis (master’s)
Grammatical differences	Present perfect tense (I’ve just eaten lunch.)	Simple past (I just ate lunch.)
	Got vs. Gotten (He’s got better at editing.)	Gotten (He’s gotten better at editing.)
	Prepositions: at the weekend, in hospital, different to	Prepositions: on the weekend, in the hospital, different from/than
	Collective nouns: The team are winning.	Collective nouns: The team is winning.
Punctuation and quotation marks	Single quotation marks for primary quotes; punctuation outside quotes	Double quotation marks for primary quotes; punctuation inside quotes
	Oxford comma used only when necessary (The study examines climate change, urbanisation and deforestation.)	Oxford comma widely used (The study examines climate change, urbanization, and deforestation.)
Formatting and style	Date: 5 November 2025, 05/11/2025; Time: 14:00 (24-hour clock)	Date: November 5, 2025, 11/05/2025; Time: 2:00 PM (12-hour clock)
	Citation styles: Harvard, Oxford, or MHRA	Citation styles: MLA, APA, Chicago
	Formatting requirements vary by institution	Formatting requirements vary by institution
Tone and style	More formal and polite: “Would you mind if…”	More direct and conversational: “Can you send this by Monday?”

Tips for writers

Know your audience

It is important to know who you are writing for. If you’re submitting an article to a UK-based publication, you should use British English. If you’re writing a blog post aimed at readers in the U.S., choose American English. International companies may even specify a preferred variant in their content guidelines.

Set your tools accordingly

Most modern writing software—such as Microsoft Word, Google Docs, and grammar tools—allow you to set your preferred language variant. Set it at the beginning of your project to avoid mixing styles. 

Use style guides for reference

Academic and professional texts are often written according to specific style guidelines. The Chicago Manual of Style, APA, and MLA are common in American institutions. The Oxford Style Manual and The Guardian Style Guide are widely used in the UK. If you know which guide to follow, many questions about spelling, punctuation, and tone can be clarified.

Avoid mixing styles

Mixing British and American spelling—such as writing “color” in one paragraph and “favour” in the next—can distract readers and come across as unprofessional. Decide on a style and stick to it throughout your text. 

Watch out for word usage

Be careful with region-specific terms. For example, if you are writing for an American audience, you should use “truck” instead of “lorry,” and “elevator” instead of “lift.” Consider keeping a reference sheet of common equivalents nearby. 

Let technology help you stay consistent 

Instead of manually checking every instance of “realise” or “organize,” let smart writing tools support you. 

Write with confidence using InstaText

If you’ve ever wanted an editor that understands the differences between British and American English, InstaText is here to help. It’s an advanced editing assistant that improves your text’s accuracy and readability while keeping your spelling, grammar, tone, and formatting consistent in the chosen English variant, all without changing your original style and voice.  

With just one click, you can switch between British and American English, and InstaText will adjust your entire text accordingly—no manual rewrites needed.If you are a user, we are happy to have you on board. We suggest you check out our blog for more writing tips and insights. If you’re not a user yet, visit InstaText.io and start writing like a pro—no matter which side of the Atlantic you’re on.

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— Dr. Michał Folwarczny, Postdoctoral Researcher

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