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Mastering parentheses usage boosts your clarity, credibility and professionalism in everything from social media posts to business emails. It can even save you from awkward (or dangerous) misunderstandings. Yet many writers aren’t sure when to use parentheses or how they differ from other punctuation.
This article will teach you all you need to know about parentheses usage and the difference between parenthesis (singular) and parentheses (plural).
Parenthesis vs parentheses in a nutshell
| Term | Definition | Example |
|---|---|---|
| Parenthesis | A single curved mark that opens or closes a parenthetical expression. Also refers to the information enclosed by parentheses. | Some authors often add a parenthesis to include extra details about a topic. |
| Parentheses | The pair of curved marks ( ) used in writing to enclose a parenthetical expression. | She finally answered (after five minutes). |
When to use parentheses (and how to do it)
1) Add supplemental information
Parentheses enclose non-essential details that can be removed without changing the core meaning of the sentence.
The History Channel (well known for its alien shows) is now for sale.
2) Clarify terms & acronyms
Parentheses can spell out acronyms or provide translations for non-English words:
The Regional Comprehensive Economic Partnership (RCEP) united 15 nations.
3) Introduce numbered items in a sentence
Use parentheses to label items within a sentence (a), (b), (c).
4) In-text citations & reference lists
Academic styles place author and date references in parentheses: (Lock, 2008). Parentheses also appear in reference-list entries for dates and formats.
5) Punctuation with complete vs incomplete sentences
If the parenthesis is a complete sentence inside another sentence, lowercase the first word and keep the period outside.
Standalone parenthetical sentences get their own period inside the marks. Question or exclamation marks stay inside if they belong only to the parenthesis.
When to avoid or replace parentheses
There are moments that parentheses complicate texts and interrupt the natural reading flow. You don’t want to confuse your reader when things are getting important.
Consider these five reasons to replace or avoid parentheses usage.
1) When the information has higher importance
Avoid using parentheses when the information is essential to the meaning of the sentence.
Wrong: The dosage (twice a day) must be respected.
Right: Take the medicine twice a day.
2) When you’re using several parentheses per sentence
Multiple parenthetical asides force readers to “jump” in and out of the main idea. Break long sentences in two or rewrite to reduce clutter.
Wrong: The symposium (originally planned for March) was postponed (because the keynote speaker fell ill) and will now take place (tentatively) in July.
Right: The symposium was originally planned for March but was postponed because the keynote speaker fell ill. It is now tentatively scheduled for July.
3) When using nested parentheses
Avoid stacking parentheses. If you need a second layer, use parentheses first and use square brackets ([ ]) inside them. This is the approach recommended by university writing guides.
Wrong: The novel (first published (self-funded) in 1978) became a bestseller).
Right: The novel (first published [self-funded] in 1978) became a bestseller.
4) In formal writing
Formal writing style uses dashes, commas or direct rewrites to keep the text clear, useful and concise.
Wrong: The CEO announced a new hiring freeze (effective immediately).
Right: The CEO announced a new hiring freeze – effective immediately.
Right: The CEO announced a new hiring freeze, effective immediately.
5) When prioritizing accessibility and reading flow
Parentheses interrupt the flow of a sentence. If you want to make your writing easier to read, avoiding parentheses is usually the right way to go.
This is especially important for people who use a computer screen reader. The screen reader will say “open parenthesis … close parenthesis” wherever you have used these marks, adding difficulty for visually-impaired readers.
Instead of using parentheses, use commas or rewrite the sentence to make things more readable.
Wrong: Please submit the form (including all attachments) by Friday.
Right: Please submit the form, including all attachments, by Friday.
Three reasons to avoid using parentheses
| Purpose | Replace parentheses with | Why |
|---|---|---|
| To add emphasis | Dashes (–) | Draws strong attention to the text between the dashes |
| To make a light aside to the reader | Commas (,) | Creates a softer break in your sentence |
| To use a more formal tone | Rewrite the sentence | Using parentheses can create a less professional tone |
Difference between parentheses and brackets
Parentheses and brackets look similar at a glance, but they serve unique roles.
Parentheses slip extra, non-essential details into your own sentences. Brackets act as an editor’s tool, quietly modifying or clarifying quoted material without altering the original words.
Look at the table below to learn when to use each mark to make accurate citations and keep your readers free from confusion.
Brackets vs parentheses usage
| Mark | Shape | Typical use | Example |
|---|---|---|---|
| Parentheses ( ) | Rounded | Add non-essential info in your own text | She adopted a dog (a rescued beagle). |
| Brackets [ ] | Square | Insert editorial words into quoted text | He [the author] believed that the moon wasn’t real. |
Remember, the “nested” rule also applies to brackets. Use both brackets and parentheses to keep punctuation clear and prevent visually confusing “double bubbles,” as in the following example:
The novel (first published [self-funded] in 1978) became a bestseller.
Parentheses, dashes or commas – which one should you use?
You should use parentheses, dashes or commas depending on the “volume” you want to broadcast. Think of them as points on a loudness scale – parentheses whisper, commas chat, and dashes shout.
Parentheses, dashes and commas
| Mark | Emphasis | When to use | Example |
|---|---|---|---|
| Parentheses | Whisper Lowest emphasis | Side remarks, clarifications and afterthoughts that readers could skip. | The launch is finally live (after two delays). |
| Commas | Conversational Neutral emphasis | Short, non-essential phrases closely tied to the main idea of the sentence. | The launch, delayed twice, is finally live. |
| Dashes | Spotlight High emphasis | Dramatic interruptions, long asides or parentheticals that already have internal commas. | The launch – delayed twice – is finally live. |
Consider the following:
Parentheses are perfect for jokes or digressions you don’t mind readers skipping.
Commas work when the aside is short and essential to the sentence flow.
Dashes highlight information or an abrupt change in direction.
With all of these punctuation marks, be careful not to use too many. Too much punctuation can make your writing difficult to read.
Style guide considerations when using parentheses
Different writing styles have different rules about parentheses. Knowing these style rules can help you write confidently and use the correct punctuation.
Below is a quick overview of how major style guides treat parentheses and what that means for your writing.
Style guide overview
| Style | Attitude toward parentheses | When to use parentheses |
|---|---|---|
| AP (Associated Press) | Use sparingly. Commas or dashes are preferred instead. | Journalism, press releases, headlines |
| Chicago Manual of Style | Can use parentheses for non-essential information. Avoid nesting parentheses. | Non-fiction, books, essays, academic works |
| APA MLA | Extensive use, especially for in-text citations (author, year, page number) | Academic papers, student essays, research writing |
Style matters when using parentheses, commas or dashes
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Common mistakes when using parentheses
Parentheses are only helpful when used with purpose and precision. Misusing them may confuse your readers, weaken your message or create grammatically incorrect sentences.
Let’s look at the most common pitfalls and how to fix them.
Using parentheses for essential information
If the content inside the parentheses is critical to the sentence’s meaning, it shouldn’t be in parentheses.
Parentheses imply, “You can skip this and still understand everything.” If that’s not true, rewrite or use commas or dashes to include the information smoothly.
Wrong: Please bring your ID (you’ll need it to enter the exam room).
Better: Please bring your ID, as you’ll need it to enter the exam room.
Better: Please bring your ID – you’ll need it to enter the exam room.
Nesting parentheses
Parentheses inside parentheses are visually confusing and hard to read.
If you need to include extra information within parentheses, use brackets ([ ]) for the inner element.
Wrong: The class (taught by Dr. Miller (who also teaches writing)) starts Monday.
Right: The class (taught by Dr. Miller [who also teaches writing]) starts Monday.
Misplaced punctuation
Where does the period go? That depends on what’s inside the parentheses.
Be extra careful with questions or exclamation marks. They should be placed inside only if they apply to the parenthesis itself.
Consider the following:
If the text inside the parentheses is part of a larger sentence, punctuation stays outside.
The results were promising (especially in the first group).
If the text inside the parentheses is a complete sentence on its own, punctuation goes inside.
The experiment was a success. (We repeated it twice to confirm.)
Overusing parentheses
If every sentence has parentheses, something’s wrong.
Overuse signals cluttered thinking and is unclear. Instead of cramming details into parentheses, look for other ways to present the information, delete it, or give it its own sentence.
Unclear: The app (which launched last year) now has new features (including a dark mode) and will (hopefully) expand globally.
Better: The app, launched last year, now includes new features like dark mode. It’s expected to expand globally soon.
Quick check list to know you’re using parentheses correctly
When writing something in English, ask yourself three questions:
1. Can I delete the information in parentheses without losing essential information?
If not, rewrite the sentence without parentheses.
2. Is the surrounding punctuation placed correctly?
Check periods, commas and question marks.
3. Would a dash or full rewrite improve clarity or flow?
Try reading the sentence aloud. If it feels clunky, it probably needs a change.
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