Commas (,) have many uses.

They are used before a conjunction to join two independent clauses:

  • Gary loves cycling, and he is a fan of Liverpool.
  • I want a job as a software developer, so I am studying at university.

They are used to add extra information not important to a sentence:

  • Mr Williams, who is the chairman, is the founder of the company.
  • Mike, my sister’s husband, will be late.

They are used to separate items in a list:

  • Please buy some beer, crisps and nuts.
  • She will visit Argentina, Paraguay and Uruguay.

They are used between two adjectives where you could use and:

  • It is a short, simple story.
    (It is a short and simple story.)
  • I have a black, steel bike.
    (I have a black and steel bike.)

They are used between three or more adjectives or adverbs:

  • I like the old, brown, wooden table.
  • He ran quickly, quietly and effortlessly.

They are used after an introductory word or phrase:

  • By evening, we were very tired.
  • I thought you were wrong. However, I now agree with you.

They are used after an interjection:

  • No, it can’t true!
  • Yes, I did! I told you twice.

They can be used with numbers over 999 to make them easier to read:

  • 1,009
  • £20,000,000

They are used for direct address:

  • Oi, Jack, get the beers.
  • Is that your sister, Micheal?

They are used before a quotation:

  • She said quietly, ‘I know.’
  • He looked at me and said, ‘I’ve seen it all and done it all.’

They are used for addresses:

  • 9 Brompton Avenue, Liverpool, L4 2PB, United Kingdom
  • Flat 21, Mansion House, Matlock, Derbyshire, DE4 2UP