Punctuation
[C1] Punctuation makes a text clearer and easier to read. We use punctuation in places a speaker
would change tone or take a brief pause. To use punctuation correctly, especially in higher level
writing such as that practised in the Writing module (e.g. Writing reports and essays or Short writing
for the workplace), you will first need to have mastered basic grammar concepts. As such, while
learning about basic punctuation concepts here, you may need to refer to information in the links
more often than in other modules.
Here, we look at the most important aspects of the following types of punctuation: the full
stop/period, question mark, comma, colon, semicolon, apostrophe, hyphen, en dash, and quotation
marks. These are the most used types of punctuation in academic and business writing. For more
extensive information about each one, or to learn about other punctuation marks, see
the Punctuation usage checklist.
Note that we offer general rules here. Style guides vary in their opinion on the correct usage of
punctuation, so always follow your organisation’s house style or preferred style guide.
Full stop/period (.)
This punctuation mark is referred to as a ‘full stop’ in British English and a ‘period’ in American
English. In addition to its main function as a sentence-final punctuation mark indicating the end of a
sentence, we can use the full stop for other purposes.
• With some abbreviations: We use full stops with certain abbreviations such as e.g.,
etc., and i.e., but not with metric measurements. If a sentence ends with an abbreviation
that uses a full stop, we do not add an additional full stop.
For more information on using a.m./am etc., see Writing dates and time.
Add 550 ml of water to the mix.
(no full stop for metric measurements)
The party ended at 1a.m.
(sentence ends with abbreviation with a full stop, so no additional full stop)
• British style and conventions generally omit the full stop when the abbreviation represents
the first and last letter of the word. American style and conventions generally add a full stop
after abbreviations.
BrE: We hired a new export manager, Mr Smith.
AmE: We hired a new export manager, Mr. Smith.
, • Not with most acronyms and initialisms: In most acronyms, the initial letters of a series of
words are pronounced as the combination is spelled. In initialisms, the individual letters are
pronounced. We generally do not add full stops to either.
NATO (acronym)
scuba (acronym)
CIA (Central Intelligence Agency; initialism)
Question mark (?)
We use this sentence-final punctuation mark in a sentence that asks a question for which a response
is expected.
• Direct, embedded and tag questions: We use a question mark after these types of questions.
While the word order in embedded questions is more like that of a statement, a response is
expected. With tag questions, use a comma before the tag and a question mark after it. We
do not use question marks for indirect questions since no response is expected.
What time will you be home?
(direct question; question mark used)
Do you know what time you will be home?
(embedded question is ‘what time will you be home’; question mark used)
You called the client back this morning, didn’t you?
(tag question; comma before the tag and a question mark after it)
Jim asked me when I would be home.
(indirect question; full stop used instead of a question mark)
• Not with most other punctuation marks: The main exception is a full stop used in an
abbreviation before a question mark. We can also combine quotation marks with question
marks. Consult your style guides to see how to combine quotation marks with question
marks in a quotation, as the guidelines differ enormously.
Is the meeting at 9a.m.?
Comma (,)
The comma frequently leads to problems. Mastering the comma is often based on knowing
when not to use one. Since the comma is the most extensively used punctuation mark, the guidelines
for its use are also extensive. For ease of learning, we have divided the guidelines into three rough
categories: connecting and isolating, listing, and miscellaneous.
Connecting and isolating
Commas are often used, and often used incorrectly, to connect or join sentences and ideas. To use a
[C1] Punctuation makes a text clearer and easier to read. We use punctuation in places a speaker
would change tone or take a brief pause. To use punctuation correctly, especially in higher level
writing such as that practised in the Writing module (e.g. Writing reports and essays or Short writing
for the workplace), you will first need to have mastered basic grammar concepts. As such, while
learning about basic punctuation concepts here, you may need to refer to information in the links
more often than in other modules.
Here, we look at the most important aspects of the following types of punctuation: the full
stop/period, question mark, comma, colon, semicolon, apostrophe, hyphen, en dash, and quotation
marks. These are the most used types of punctuation in academic and business writing. For more
extensive information about each one, or to learn about other punctuation marks, see
the Punctuation usage checklist.
Note that we offer general rules here. Style guides vary in their opinion on the correct usage of
punctuation, so always follow your organisation’s house style or preferred style guide.
Full stop/period (.)
This punctuation mark is referred to as a ‘full stop’ in British English and a ‘period’ in American
English. In addition to its main function as a sentence-final punctuation mark indicating the end of a
sentence, we can use the full stop for other purposes.
• With some abbreviations: We use full stops with certain abbreviations such as e.g.,
etc., and i.e., but not with metric measurements. If a sentence ends with an abbreviation
that uses a full stop, we do not add an additional full stop.
For more information on using a.m./am etc., see Writing dates and time.
Add 550 ml of water to the mix.
(no full stop for metric measurements)
The party ended at 1a.m.
(sentence ends with abbreviation with a full stop, so no additional full stop)
• British style and conventions generally omit the full stop when the abbreviation represents
the first and last letter of the word. American style and conventions generally add a full stop
after abbreviations.
BrE: We hired a new export manager, Mr Smith.
AmE: We hired a new export manager, Mr. Smith.
, • Not with most acronyms and initialisms: In most acronyms, the initial letters of a series of
words are pronounced as the combination is spelled. In initialisms, the individual letters are
pronounced. We generally do not add full stops to either.
NATO (acronym)
scuba (acronym)
CIA (Central Intelligence Agency; initialism)
Question mark (?)
We use this sentence-final punctuation mark in a sentence that asks a question for which a response
is expected.
• Direct, embedded and tag questions: We use a question mark after these types of questions.
While the word order in embedded questions is more like that of a statement, a response is
expected. With tag questions, use a comma before the tag and a question mark after it. We
do not use question marks for indirect questions since no response is expected.
What time will you be home?
(direct question; question mark used)
Do you know what time you will be home?
(embedded question is ‘what time will you be home’; question mark used)
You called the client back this morning, didn’t you?
(tag question; comma before the tag and a question mark after it)
Jim asked me when I would be home.
(indirect question; full stop used instead of a question mark)
• Not with most other punctuation marks: The main exception is a full stop used in an
abbreviation before a question mark. We can also combine quotation marks with question
marks. Consult your style guides to see how to combine quotation marks with question
marks in a quotation, as the guidelines differ enormously.
Is the meeting at 9a.m.?
Comma (,)
The comma frequently leads to problems. Mastering the comma is often based on knowing
when not to use one. Since the comma is the most extensively used punctuation mark, the guidelines
for its use are also extensive. For ease of learning, we have divided the guidelines into three rough
categories: connecting and isolating, listing, and miscellaneous.
Connecting and isolating
Commas are often used, and often used incorrectly, to connect or join sentences and ideas. To use a
