Knowing when to use a comma with a clause in a
sentence can be a confusing matter. To understand if
punctuation is needed, it is important to understand
the different types of clauses and to understand
their purpose in the sentence. Before we begin, some
definitions are required.
Clause – A clause is a series of related
words that contain a subject and a predicate.
Sometimes a clause is independent, meaning it can
stand alone as a complete sentence. Other times the
clause is dependent, meaning it can't stand alone as
a sentence, but serves or functions as an adverb,
adjective, or a noun within a sentence. Such clauses
can be of two types – restrictive and
Restrictive Clause – A clause that in some
way limits a word or words referred to, either by
setting conditions or limiting the word to a certain
group or specific item.
What this means is that the clause is necessary for
the sentence’s meaning. Because the information is
required for the meaning to be complete, it should
never be separated from the rest of the sentence
with a comma or commas.
Ex. – Bruce even includes a chapter on the number of
individuals who began to visit the South as a
In this example, the subordinate clause (bolded) is
restrictive because Bruce included only a certain
kind of individuals – those who visited the South in
the winter. Without the clarification provided by
the restrictive clause, the sentence would be vague
Nonrestrictive Clause – A clause that is not
essential to the meaning of the word or words
Unlike a restrictive clause, nonrestrictive clauses
merely add information. They are not necessary for
the full meaning of the sentence to be clear. Since
this is the case, a comma or pair of commas is
Ex. – The first was Bailyn’s addition to show that
the inherited oppositional thought, which he
claims had been apparent in American polity since
the early eighteenth-century, differed from
mainstream English thought.
As a way of demonstrating the properties of a
nonrestrictive clause, look at the same sentence
with the clause removed:
The first was Bailyn’s addition to show that the
inherited oppositional thought differed from
mainstream English thought.
As you can see, the sentence still makes sense and
its meaning is clear without the clause. It gets
across the main information the writer wanted the
reader to know. The nonrestrictive clause simply
adds to the information.
earned her BA at the University of Houston-Victoria and
is pursuing graduate studies at Texas A&M University-Corpus
Christi. She has worked as a writing tutor at the Academic
Center for two years.
(1983). The Little Rhetoric & Handbook with Readings.
Glenview, IL: Scott, Foresman and Company.
Horner, W.B., Webb, S.S., & Miller, R.K. (1998) Harbrace
College Handbook. (13th Ed.) Fort Worth, TX: Harcourt
Brace College Publishers.