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Commas vs. Parentheses vs. Dashes

Neha Karve

Updated October 27, 2022

Summary

Commas, parentheses, and dashes can all be used to enclose additional information. Use commas to clarify your main idea and integrate a description into the flow of your sentence. Use parentheses to present supplementary information or an afterthought and set it off from the surrounding text. Use dashes to make information stand out. Dashes are less formal and more emphatic and dramatic than commas and parentheses.

Parenthetical punctuation

Commas, parentheses, and dashes can all be used to enclose parenthetical or optional information in a sentence. Such information is essential neither to the meaning nor to the grammar of a sentence, which means that the sentence would read perfectly fine if you removed this information.

Although parenthetical information is not essential, it can still be useful or interesting to the reader. Depending on the relevance of the information being provided, it can be set off using commas, parentheses ( round brackets), or em dashes.

Commas vs. parentheses

Use commas when you want to integrate additional information into the flow of your sentence. Use parentheses instead if you want to set off supplementary information from the rest of the text, making it less important. Commas are used to describe and clarify the main idea of the sentence. Parentheses generally mark an afterthought or other optional text—information added later to a sentence.

Integration vs. separation

While commas integrate information into the flow of your sentence, parentheses separate and subordinate it. Commas are more commonly used and less disruptive to the flow of a sentence than parentheses.

Parentheses for clarity

Parentheses may be used to set off a phrase that already contains commas. Using parentheses instead of commas to enclose such a phrase can improve readability.

Around abbreviations and definitions

Both parentheses and commas can be used to introduce an abbreviation or provide a definition. As usual, information enclosed in commas is read with the flow of the sentence, while parentheses set it off from the rest of the text.

Commas and parentheses vs. dashes

Use em dashes instead of commas and parentheses if you want to make information stand out. Commas allow for a smoother read than dashes, which interrupt the sentence to draw the reader’s attention. Parentheses diminish the importance of a phrase, while dashes enhance it.

All three punctuation marks—commas, parentheses, and dashes—can present the same information: which punctuation you use depends on how integrated you want the information to be with the rest of the sentence and how much attention you want to draw to it.

Considerations of formality

Commas and parentheses, which are quieter, are preferred in formal texts (such as academic and business writing), although they are also frequently used in informal writing. Em dashes, which are more emphatic and dramatic, are seen mainly in informal and creative writing.

Dashes for clarity

Like parentheses, dashes may be used instead of commas to set off a phrase that contains internal commas. Using dashes instead of commas can then improve clarity and help avoid confusion.

To mark an interruption or aside

Dashes can also mark an interruption or an aside. Commas cannot be used in this way. Parentheses can mark an interruption, but dashes make the idea stand out, while parentheses subordinate it.

Em dash instead of colon

An em dash can also replace a colon in a sentence to introduce new information that explains or builds upon what precedes it. Parentheses and commas cannot be used in this way. (The colon is quieter and preferred in formal usage; the dash is louder and more dramatic.)