which, who and that

Use which for things and who for people. Use that for things and, informally, for people.

When do you need a comma before which and who?

If the who or which clause is just additional information (i.e., you would be happy to put it in brackets), then you should offset it with commas.

Which, That and Who

The words which, who, and that are grammar villains — they are often the cause of grammar errors. Most commonly, this stems from confusion over whether to use a comma before which or who. Unfortunately, the rules are not simple. They are explained in more detail in the following lessons:

(A lesson providing an overview of which, that, and who)

(A lesson focusing on when to use commas with which and who)

No commas before which and who.
(A lesson focusing on when not to use commas with which and who)

These lessons are all quite similar, but they approach the issue from slightly different perspectives.

A Quick Test


Here is a quick summary of when to use a comma with which (and who):

Comma After. If the clause (shown in bold below) is required to identify whatever it follows (car in this example), then there are no commas. Use That If You Want. If you think the word that sounds better than which, then use that (provided there are no commas).

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See Also

No commas before which and who List of easily confused words