When and how to use capital letters can be a thorny problem. It may be acceptable to drop capital letters when writing casually to friends but if you are writing anything more formal then you need to use capital letters correctly.

This page lists the rules, and provides examples of when to use (and when not to use) capital letters in English writing.

 

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When to Use Capital Letters

Rule 1:

To Start a Sentence

There are no exceptions to this rule.

This means that, after a full stop, you always use a capital letter.

If the previous sentence ends with a question mark or exclamation mark, you should also use a capital letter, ? and !, like full stops, indicate the end of a sentence. However if in the sentence you have a clause in parenthesis (brackets) or sequence separated by dashes, and if these end with a question mark or exclamation mark, you should continue with lower case after the second bracket or dash.

Is it always necessary to use capitals to start a sentence? The answer is definitely yes.

She told herself – was it acceptable to talk to oneself? – that the answer was obvious.

The use of a capital after a colon (:) varies depending on whether you are writing in British or US English, just as the spelling of 'capitalisation' and 'capitalization' are different in British and US English.

You should use a capital letter after a colon with US spelling but not with UK spelling.

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Rule 2:

Titles

In titles, capitalise only the important words, not minor words such as ‘and’ and ‘but’.

‘Title Case’, with all the important words capitalised, is rather out of fashion at the moment. Most academic journals and standard referencing systems, for instance, prefer what is known as ‘sentence case’, with a single initial capital.

However, it’s good to understand the rules, in case you are required to use title case at any point.

Using the title of this article as an example:

Sentence case: “When to use capital letters”

Title case: “When to Use Capital Letters”

In title case, in this example, ‘Use’, although small, is an important word in the title, and should therefore be capitalised. ‘To’, however, is not important and therefore not capitalised.

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Rule 3:

For Proper Nouns

Proper nouns name something specific, for example, Jane, John, Oxford University, Denver, Qantas, Microsoft, Everest, Sahara. See our pages on Grammar for more information.

Proper nouns (nearly) always start with a capital letter. There are exceptions to this rule and in marketing sometimes lower-case characters are purposefully used for some proper nouns. Examples include iPhone, eBay and oneworld Alliance. However, in most cases, proper nouns start with a capital letter.

Caution is needed however, even when you are referring to a specific place or thing. If you use the more general noun rather than the proper noun, this should not be capitalised.

Further examples:

“I went to the University of Oxford today.”

“I went to Oxford today and had a look at the university.”

Capitalising is correct in both sentences. In the first the proper noun 'University of Oxford' is used.

In the second sentence, the more general noun ‘university’ is used and so it is not capitalised.

The word 'I' is not a proper noun, it's a pronoun. In English 'I' is always capitalised. In many other languages the equivalent word is not capitalised.

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Rule 4:

Acronyms

Acronyms generally work like title case: you capitalise the important words, and not ‘and’, ‘of’, ‘for’ and so on.

The easiest way to work this out is to write out the full title, and then you can see which words don’t need to be capitalised.

To make this clear, here are some examples:

British Broadcasting Corporation	BBC
Department for Education	DfE
Manchester United Football Club	MUFC
United Arab Emirates	UAE
Ministry of Transport [test]	MoT [test]
Head of Department	HoD
World of Warcraft	WoW

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Rule 5:

Contractions

For contractions, capitalise the initial letters of words, but not subsequent letters within the same word.

Contractions are like acronyms, but also include one or more letters from within the same word. Examples of this include HiFi, which is short for ‘High Fidelity’, and SciFi, short for science fiction.

The way to deal with these is to write out the phrase and have a look. Although the words that are abbreviated may not be capitalised, as in ‘science fiction’, the abbreviation always contains capitals for the start of each new word to make the word boundaries and pronunciation clear. We frequently use SkillsYouNeed, contracting the spaces but making the phrase easier to read.

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Rule 6:

Overusing Capitals is Rude

WRITING ENTIRELY IN BLOCK CAPITALS IS SHOUTING, and it’s rude.

We’ve all done it: left the Caps Lock on while typing. But in email etiquette, online chats and/or forum posts, writing in capitals is the online equivalent of shouting. It’s rude, so best not to do it unless you really do want to shout at someone. Even then, consider whether you’d really do it if that person was in front of you, and also whether it will get you anywhere.

Although it’s usually best to avoid writing in capitals, it can be useful to write odd words in capitals to give them emphasis. HELP! You're going to LOVE the surprise.

It’s also much harder to read block capitals as all the letters are the same height, so you will make your point much more easily if you use lower case.

Sometimes, especially when completing a handwritten form, BLOCK CAPITALS are preferred since this can make data entry or automatic computer recognition of handwriting easier and more accurate.

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One Final Word of Advice

Following these rules will generally help you to work out when to use capital letters.

If, however, you are still in doubt, Google the exact phrase, including capitals, and see what comes up. Although some of what you find may be wrong, you can see the general consensus and that will probably be acceptable.

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