A restrictive clause is a clause which functions as an adjective to identify the word it modifies. A restrictive clause is essential for the intended meaning. A restrictive clause is not offset with commas. For example:
Examples of Restrictive ClausesHere are some more examples of restrictive clauses:
Which, that, and who are called relative pronouns. With a restrictive clause, you can often remove the relative pronoun entirely.)
Some More Examples of Restrictive ClausesHere are some more examples of restrictive clauses in real-life quotes (restrictive clauses shaded):
What is a clause?
What is a modifier?
What are non-restrictive clauses?
More about using commas with which, that, and who
More about your choice of parentheses
Glossary of grammatical terms
Click on the one with a restrictive clause in bold:
IF YOU'RE HAPPY TO USE PARENTHESES (BRACKETS), USE COMMAS
There is often confusion over whether to use a comma(s) with a clause that starts with which or who.
If you would happily offset your clause with parentheses (brackets), then use commas. This trick works because non-restrictive clauses (the ones with commas) just provide additional information. They're not essential.
Read more about your choice of parentheses.
COMMAS AFFECT THE MEANING
The meaning of your sentence will be affected by your decision whether to use commas around a clause. Both of the examples below are grammatically sound, but they have slightly different meanings.