Misplaced punctuation kills good writing.
A comma in the wrong spot changes your meaning. Missing quotation marks confuse readers about who’s speaking. Apostrophes in plurals make you look careless.
Here are the common punctuation mistakes, and how you can make sure they don’t end up in your essay or blog post.
Commas
Commas direct readers when to pause, helping clarify relationships between ideas. Yet they’re also the source of countless writing mishaps that can transform clear sentences into confusing puzzles.
Mistake #1: The Comma Splice
A comma splice happens when you stick two complete sentences together with only a comma between them, creating a grammatical collision that confuses readers.
This happens because each part of your sentence could stand alone, but you’ve only given them a comma to lean on instead of correct support.
Wrong: The meeting ran late, everyone was getting restless.
Correct: The meeting ran late, so everyone was getting restless.
Mistake #2: Missing Commas in Series
When you list three or more items, you need commas between each one. The comma before the final item (the Oxford comma) is optional. Many academic and business styles recommend it, while journalistic styles often omit it. The key is consistency.
Wrong: She bought apples oranges bananas and grapes at the farmers’ market.
Correct (Oxford): She bought apples, oranges, bananas, and grapes at the farmers’ market.
Correct (AP style): She bought apples, oranges, bananas and grapes at the farmers’ market.
Mistake #3: Unnecessary Commas with Essential Information
Writers often insert commas around information that’s actually crucial to the sentence’s meaning. This creates awkward pauses and suggests that important details are just optional additions.
Wrong: Students, who fail to submit assignments on time, will receive grade reductions.
Correct: Students who fail to submit assignments on time will receive grade reductions.
Mistake #4: Address, Title, and Number Formatting
Addresses, job titles, and large numbers follow specific comma rules that many writers skip or apply inconsistently.
- In addresses, separate the street from the city and the city from the state.
- With titles, some styles (Chicago) use commas around titles after names (John Smith, CEO, …), while others (AP) omit them (CEO John Smith …).
- For numbers over 999, commas are used every three digits in U.S. English; in some international and scientific contexts, spaces are preferred.
Wrong: She moved to 123 Main Street Austin Texas 78701 last month.
Correct: She moved to 123 Main Street, Austin, Texas 78701 last month.
Wrong: John Smith CEO will speak at the conference about the company’s 15000 new customers.
Correct: John Smith, CEO, will speak at the conference about the company’s 15,000 new customers.
Semicolons
Semicolons are connectors that bridge related thoughts with more finesse than periods but stronger separation than commas. They’re particularly useful for creating rhythm and showing relationships between closely connected ideas.
Mistake #1: Semicolon Overreach
Many writers mistakenly use semicolons where commas belong, especially when connecting a complete sentence to a fragment. Remember, semicolons demand complete thoughts on both sides.
Wrong: The project deadline approaches; making everyone nervous about completion.
Correct: The project deadline approaches; everyone feels nervous about completion.
Mistake #2: Comma Confusion in Complex Lists
When list items contain internal commas, semicolons provide the clarity needed to distinguish between different levels of information.
Wrong: The conference attendees came from Portland, Oregon, Austin, Texas, and Miami, Florida.
Correct: The conference attendees came from Portland, Oregon; Austin, Texas; and Miami, Florida.
Quotation Marks
Quotation marks frame direct speech and indicate borrowed text, but they often appear in places where they don’t belong or disappear when they’re actually needed. Understanding their proper placement prevents confusion about who said what and when you’re using someone else’s words.
Mistake #1: Quotation Overkill for Emphasis
Writers frequently surround ordinary words with quotation marks, thinking this adds emphasis or importance. Instead, this suggests sarcasm or uncertainty, making your writing appear tentative or mocking.
Wrong: We serve only the “freshest” ingredients in our restaurant.
Correct: We serve only the freshest ingredients in our restaurant.
Mistake #2: Punctuation Placement Chaos
American and British English follow different rules about where punctuation goes relative to quotation marks.
- American English: Periods and commas always go inside quotation marks.
- British English: Periods and commas only go inside if they are part of the quoted material.
American English Wrong: She said the presentation was “absolutely brilliant”.
American English Correct: She said the presentation was “absolutely brilliant.”
British English Correct: She said the presentation was “absolutely brilliant”.
Exclamation Points
Strategic placement of exclamation points makes your genuine excitement or urgency stand out, while excessive use makes everything seem artificially dramatic.
Mistake #1: Exclamation Overload
Writers sometimes pepper their text with multiple exclamation points, thinking more marks equal more enthusiasm. This approach actually weakens your message and makes your writing appear unprofessional or desperate for attention.
Wrong: Thank you so much for your help!!! I really appreciate it!!!
Correct: Thank you so much for your help! I really appreciate it.
Colons
Colons introduce what follows, whether that’s a list, explanation, or elaboration of the preceding statement. They create anticipation and signal that important information is coming, but only when used correctly.
Mistake #1: Unnecessary Colon Interruptions
Writers sometimes insert colons after verbs or prepositions, interrupting the natural flow of sentences. Colons should only follow complete statements that can stand independently.
Wrong: The ingredients include: flour, sugar, eggs, and butter.
Correct: The ingredients include flour, sugar, eggs, and butter.
Mistake #2: Missing Colons Before Lists
When you announce that a list or explanation follows, readers expect a colon to signal this transition. Omitting this punctuation mark creates awkward sentence flow and confusion about structure.
Wrong: You’ll need three things patience, practice, and persistence.
Correct (colon needed): You’ll need three things: patience, practice, and persistence.
Dashes
Em dashes and en dashes serve different purposes, though many writers use hyphens for everything or mix up these distinct marks.
Mistake #1: Confusing Hyphens, En Dashes, and Em Dashes
These three marks may look similar, but they serve completely different purposes.
- Hyphens (-) connect compound words and break words at line endings.
- En dashes (–) show ranges and connections between equal elements.
- Em dashes (—) create strong breaks in sentences or replace commas for emphasis.
Wrong: The 1990-2000 decade was marked by rapid growth—especially in the high-tech industry.
Correct: The 1990–2000 decade was marked by rapid growth—especially in the high-tech industry.
Mistake #2: Hyphen Substitution
Many writers use regular hyphens in place of em dashes, resulting in cramped-looking text that lacks visual separation. Remember, em dashes create breathing room and emphasize interruptions or asides more clearly.
Wrong: The results – which surprised everyone – exceeded all expectations.
Correct: The results—which surprised everyone—exceeded all expectations.
Mistake #3: En Dash Confusion
En dashes connect ranges and relationships between equal elements, but writers often substitute hyphens or em dashes. This creates inconsistency and can confuse readers about the relationships you’re describing.
Wrong: The New York-London flight takes approximately eight hours.
Preferred: The New York–London flight takes approximately eight hours.
Note: Some U.S. publishers accept a hyphen instead.
Quick tip: Create an em dash by typing two hyphens or using Alt+0151 on Windows, Option+Shift+Hyphen on Mac. For en dashes, use Alt+0150 on Windows or Option+Hyphen on Mac.
Apostrophes
Apostrophes indicate possession and contractions, yet they frequently appear in plurals or disappear from possessives. These mistakes are particularly noticeable because they affect meaning and suggest a lack of care in applying basic grammar rules.
Mistake #1: Plural Apostrophe Mixup
Writers often add apostrophes to regular plurals, creating possessive forms where none belong. This mistake is so common that it has earned the nickname “greengrocer’s apostrophe” for its frequent appearance on market signs.
Wrong: We sell fresh tomato’s and potato’s daily.
Correct: We sell fresh tomatoes and potatoes daily.
Mistake #2: Its vs. It’s Confusion
The distinction between “its” (possessive) and “it’s” (contraction) trips up many because possessive nouns typically use apostrophes. However, possessive pronouns follow different rules that create this exception.
Important: its’ is never correct in standard English.
Wrong: The dog wagged it’s tail when it saw its’ owner.
Correct: The dog wagged its tail when it saw its owner.
Mistake #3: Unclear Possessive Endings
Words ending in “s” create confusion about apostrophe placement, leading to inconsistent possessive forms. Style guides disagree, so pick one and be consistent.
- Chicago Manual of Style: James’s car.
- AP Style: James’ car.
Wrong: James’s car and the Jones’ house both need repairs.
Correct (Chicago): James’s car and the Joneses’ house both need repairs.
Correct (AP): James’ car and the Joneses’ house both need repairs.
Parentheses
Parentheses contain supplementary information that enhances but doesn’t disrupt the main sentence flow. They’re useful for clarifications and additional details, but incorrect usage can create unwanted interruptions.
Mistake #1: Overuse of Parenthetical Asides
Some writers rely too heavily on parentheses, creating choppy text that is both distracting and difficult to read and comprehend.
Wrong: The presentation (which lasted two hours) covered budget projections (including quarterly forecasts) and staffing changes (both additions and departures) for next year.
Correct: The two-hour presentation covered budget projections, including quarterly forecasts, and staffing changes for next year.
Mistake #2: Punctuation Placement Problems
Writers often struggle with where to place punctuation when parentheses are involved, creating inconsistent patterns that confuse readers about sentence structure and completion.
- If the parenthetical is part of the sentence, punctuation goes outside.
- If the parenthetical is a complete sentence, punctuation goes inside.
Correct (part of sentence): The meeting starts at 9 AM (please arrive early).
Correct (complete sentence): The meeting starts at 9 AM. (Please arrive early.)
Free Punctuation Checker
Want to correct all your punctuation errors? You don’t have to pay for an AI punctuation checker; enter our punctuation check prompt to ChatGPT.
You are a proofreader. Your task is to identify and correct all punctuation errors in my text below. Please keep in mind that my text follows [AP/APA/Chicago/MLA] style.
[insert text]Master Punctuation for Clearer Communication
There you have it! Punctuation marks might seem insignificant compared to word choice and sentence structure, but one incorrect punctuation mark can make your readers struggle to understand what you’re trying to say.
Need more help with the editing process? Learn how to use ChatGPT as a grammar checker.