In plain English
When do you use a comma, a semicolon or a colon?
The Simple Answer
Use a comma for a short pause inside a sentence, such as between items in a list. Use a semicolon to join two complete sentences that belong together. Use a colon after a complete sentence to introduce what comes next: a list, an explanation or an example.
All three marks sit in the middle of a sentence, and they look alike, which is why they get mixed up. The difference is the job each one does. A comma separates, a semicolon connects, and a colon points forward.
| Mark | Its job | Example |
|---|---|---|
| Comma , | Separates items or parts of a sentence | We packed bread, cheese and fruit. |
| Semicolon ; | Joins two complete sentences that are closely related | The road was icy; we drove slowly. |
| Colon : | Introduces what the first part promised | We packed three things: bread, cheese and fruit. |
The comma: a short pause
The comma is the most used mark and the easiest to overuse. These four jobs cover most of what you will write.
- Items in a list: "We bought apples, bread and milk."
- Two full sentences joined by a word such as and, but, or, so: "It rained, so we stayed in."
- An opening phrase: "After lunch, we went for a walk."
- Extra information that could be removed: "My sister, who lives in Ohio, is visiting."
Whether to put a comma before the last "and" in a list (the Oxford comma) depends on the style guide. Pick one habit and keep it.
The semicolon: two sentences that belong together
A semicolon works like a soft full stop. What sits on each side should be able to stand alone as a sentence, and the two ideas should be closely linked.
Joining two related sentences
Two sentences: "The meeting ran late. Nobody minded."
Joined with a semicolon: "The meeting ran late; nobody minded."
With a linking word: "The meeting ran late; however, nobody minded."
Words such as however, therefore and instead usually follow a semicolon and then take a comma after them. A plain and, but or so does not need a semicolon; a comma is enough.
There is a second use. When the items in a list already contain commas, semicolons keep them apart so the list stays readable.
A list with commas inside the items
Confusing: "We visited Paris, France, Rome, Italy, and Madrid, Spain."
Clear: "We visited Paris, France; Rome, Italy; and Madrid, Spain."
The colon: here comes the explanation
A colon says "here is what I just promised." What comes before it should be a complete sentence. What comes after can be a list, a single word, a phrase or another sentence.
- A list: "You need three things: eggs, flour and sugar."
- An explanation: "There was one problem: the door was locked."
- A quotation or example: "Her advice was simple: ask early."
Do not put a colon straight after a verb or a word like "such as". "You need: eggs, flour and sugar" breaks the sentence in the wrong place. Write "You need eggs, flour and sugar" or "You need these: eggs, flour and sugar."
A quick test for choosing
- Can you say the part before the mark as a complete sentence? If not, you almost certainly need a comma, or no mark at all.
- If both parts are complete sentences, are they closely linked? Use a semicolon, or a full stop if you want a firmer break.
- Is the first part a complete sentence that sets up what follows (a list, a reason, an example)? Use a colon.
Three common mistakes
| Mistake | Fix |
|---|---|
| The comma splice: "I was tired, I went to bed." | Use a semicolon, a full stop, or add a word: "I was tired, so I went to bed." |
| A semicolon before a fragment: "I like tea; especially green." | Use a comma: "I like tea, especially green." |
| A colon after an incomplete sentence: "My favorites are: red and blue." | Drop the colon: "My favorites are red and blue." |
Try it yourself
Pick the right mark for each gap, then check the answers below.
- She loved the city __ it was loud, busy and alive.
- Before you leave __ check the stove.
- There is only one rule here __ be kind.
Answers: 1, a semicolon (two related sentences) or a colon (the second explains the first). 2, a comma after the opening phrase. 3, a colon, because the second part explains the rule.
Style guides disagree on a few small points, such as whether to capitalize the first word after a colon. When you write for a class, a publisher or an employer, follow the guide they name.