Start a sentence (including full-sentence quotations) with a capital letter.
Use a capital letter at the start of a sentence. (This includes sentences within quotation marks.)

The words following a colon do not usually start with a capital letter, unless the introduction is short and the words after the colon are the main idea and a complete sentence.

A Capital Letter to Start a Sentence

Each new sentence should start with a capital letter.  This also applies to sentences contained within quotation marks.


At 4 o'clock, he stood up and said: "You can all leave if you wish."
He was considered "The sexiest man ever to come out of Barnsley".

Capital Letters after Colons

The words which are introduced by a colon do not usually start with a capital letter. For example:

  • In this world there are only two tragedies: one is not getting what one wants, and the other is getting it. (Oscar Wilde)
However, when the introduction is short and the words which follow the colon are the main idea and a standalone sentence, then it is possible to use a capital letter for style purposes. For example:

  • Our motto: Live every day to the fullest – in moderation. (Lindsay Lohan)
There is a lot of leniency on this. If you feel a capital letter is right, use it. If you think it looks awkward, go for a lowercase letter. If the first word should have a capital letter in its own right (e.g., it's a proper noun (like London, George Harrison, Wal-Mart) or an abbreviation (like CNN, BBC, Nato), then obviously it keeps its capital letter.

Once you have expressed a complete idea, you should put a full stop and end the sentence. Do not insert a comma and continue writing. This is a very common mistake.

John sprang to his feet and ran to the shop, he needed to buy more beer before the second half started.

The Loch Ness Monster was spotted 8 times in the '60s, I camped there for a year and did not see a thing, I caught dozens of trout though.
Occasionally, it may be appropriate to use a dash or a semicolon instead of a full stop and then continue writing.

See the lesson Extend a Sentence.

The word however (usually written However,) nearly always starts a new sentence. It is a common mistake to merge sentences using however.

I am leaving on Tuesday, however, I will be back on Wednesdayto collect my wages.

I am leaving on Tuesday. However, I will be back on Wednesday to collect my wages.
Do not feed the fish in this tank, however, you may feed the animals in the petting zoo.
The centre forward is very fast. However, he can only kick the ball with his left foot.

Occasionally, it may be appropriate to use a dash or a semicolon before however.

See the lesson Extend a Sentence.


Be aware that the word however does not always start a new sentence.
John has confirmed that he can attend the meeting on Saturday. Simon, however, is out of the country until Monday.

See the lesson Parenthesis

See also:

Capital letters in advertisements
Capital letters and the points of the compass
Using capital letters with proper and common nouns
Capital letters with the four seasons
What is title case?
Test on using capital letters