There's a good chance you punctuate poorly and don't realize it.

This page will fix your mistakes. It covers the top ten rules of punctuation.

But let's first consider why you should care about punctuation:

Good writing is an indicator of an organized mind that is capable of arranging information in a systematic fashion to help other people understand things. —Dustin J. Mitchell

Clear writing leads to clear thinking. You don’t know what you know until you try to express it. —Michael A. Covington

If you are deciding between two people to hire, always choose the better writer. Assuming they are equally qualified, the better writer will communicate work issues more clearly. This extends to emails, messages—frankly, everywhere. —David Heinemeier Hansson

Don't take punctuation too seriously

Let’s also clarify what’s not important: the lesser-known rules of grammar and punctuation that instruct us to write in ways that differ from everyday speech .

In practice, no one cares if you start a sentence with “and” — because that’s how people talk. By definition, there’s usually no loss in clarity by communicating naturally.

There is, however, loss of clarity when transposing speech to writing without respect for the purpose of punctuation: being clearly understood.

You're about to see how misusing punctuation not only confuses readers but also marks you as someone who doesn’t pay attention to detail. 

Let's begin with punctuation rule number one. I'm going to use absurd examples to keep this post fun.

1. Separate danglers with a comma

A “dangler” is my term for a word located at the extreme end of a sentence that either:

• A) addresses someone being spoken to, or
• B) answers a question with an affirmative (yes) or negative (no) word

Examples of addressing someone being spoken to

Correct: “Matt, you eat way too many pimply pickles.”

Correct: “Why do you keep flicking my belly button, Matt?”

In both examples, the person being spoken to is referenced at either extreme end of the sentence. Notice that the word used to address the person (e.g. “Matt”) is separated from the rest of the sentence with a comma. 

Always do this. If you don’t, you could run into the following problem:

Potentially confusing: “Let’s eat grandpa.”

Very clear: “Let’s eat, grandpa.”

Potentially confusing: “Where’s the kitchen Matt?”

Very clear: “Where’s the kitchen, Matt?”

Notice how the above two sentences have entirely different meanings based on the presence of a comma. The confusing example can be mistaken for, “Where is the kitchen mat [that I stand on while cooking]?” as opposed to, “Hey, Matt, where exactly is the kitchen located?”

Comma rules make up the bulk of this page. Because not knowing when to use a comma is the most common punctuation mistake.

Examples of answering a question with an affirmative or negative

Correct: “Yeah, he smelled like rabies and burned sausage.”

Correct: “Correct, I’m still waiting for Santa Claus’ therapist.”

Correct: “I don’t know what you’re talking about, no.”

In the above examples, a positive (“yes”, “yeah”, “sure”, “correct”, etc.) or negative (“no”, “nah”, “nope”, “incorrect”, etc.) word begins or ends the sentence. As when addressing someone, always separate the affirmative or negative word from the rest of the sentence using a comma. 

If you don’t, you could end up with confusion:

Potentially confusing: “No one is still here.”

Clear: “No, one is still here.”

In the first example, you’re stating that nobody is here. In the second, you’re responding to a question in the negative (“no”) then clarifying that “one [person] is still here.”

2. If you can, use a period instead of a comma

Never use a comma or a hyphen if using a period in its place wouldn’t change the sentence’s intended meaning. Following this rule will help you avoid several grammar mistakes.

Consider these examples:

Incorrect: “I don’t know why he’s singing, he’s next-level awful.”

Incorrect: “I’m not a liar, I just don’t respect the truth.”

Incorrect: “I have a hunch that you rollerblade ,  am I right?”

Incorrect: “Why would you smack a badger, that’s dangerous.”

Read through those sentences once more. This time, imagine replacing each comma or hyphen with a period. The statements continue to read perfectly, right? The sentences’ meanings don’t change at all, right? 

Awesome. Then use that period instead of the comma/hyphen, and you’ve just confidently avoided improper comma usage!

(I’m not going to dive into how it is that you’re avoiding punctuation errors because that would necessitate a discussion on clauses, and I want to keep this guide short.)

Here are the fixed examples:

Correct: “I don’t know why he’s singing. He’s next-level awful.”

Correct: “I’m not a liar. I just don’t respect the truth.”

Correct: “I have a hunch that you rollerblade. Am I right?”

Correct: “Why would you smack a badger? That’s dangerous.”

The takeaway is that unless you’re an experienced writer, train yourself to always take a second look whenever you use a comma or a hyphen. Ask yourself, “Can I replace this with a period?” If so, do it. This is the most important comma rule.

3. In a list, use a comma before the final “and”

When you have a series of items separated by commas, ensure that you place a final comma (an “Oxford comma”) before and:

Correct: To my parents, Jeff Bridges, and Wonder Woman.

Incorrect: To my parents, Jeff Bridges and Wonder Woman.

In the correct example, you’re dedicating a book to your parents, and Jeff Bridges, and Wonder Woman. That’s three individual people.

In the incorrect example, you’re dedicating a book to your parents who you’re then identifying as Jeff Bridges and Wonder Woman. The lack of a concluding comma inadvertently changes the entire meaning of your sentence.

Takeaway: At the end of a list of items, always use a comma before the final “and.”

4. Use a comma before introducing a question

Place a comma before introducing a question — regardless of whether the question is wrapped in quotation marks:

Correct: I’ve been wondering, Why is that turtle so nasty?

Incorrect: I’ve been wondering why is that turtle is so nasty?

Correct: He was wondering, “Where are my hands?”

Also, capitalize the first letter of the question (e.g. the "W" in "Why"). In the first example, this helps delineate the question so that it's interpreted outside the context of the containing sentence.

Tip: Quotes only surround a question when you’re word-for-word quoting something that was said. If you’re instead hypothetically posing a question, as is the case in the first example, then quotes are not needed.

5. Don’t use a comma to represent vocal pauses

Commas serve many purposes, but representing arbitrary pauses in speech is not one of them. For example, this is not when you should use a comma:

Incorrect: “It’s a tough day in a man’s life, when he finds out he’s a robot.”

Correct: “It’s a tough day in a man’s life when he finds out he’s a robot.”

The above sentence might be spoken with a pause between the words “life” and “when” in order to provide dramatic effect, but a comma is the wrong form of punctuation to capture a pause. Instead, an ellipsis (…) would be appropriate:

Correct: “It’s a tough day in a man’s life… when he finds out he’s a robot.”

The easiest way to avoid misusing commas in this manner is to ask yourself if using the comma makes the sentence read like a haiku. If so, replace it with an ellipsis or drop it altogether.

This leads into the next rule…

6. Don’t use ellipses

An ellipsis is a trio of periods (…).

Don’t use it—unless you're quoting someone. You rarely see it used in textbooks , because it’s the sign of a lazy writer failing to structure their thoughts so that they fall within the lines of more common punctuation. 

In essence, the writer is falling back on free-form speech patterns. Speaking of which, that's the one place it’s okay to use an ellipsis: inside a quote.

For example, she said to me, “Linda… You need to get rid of that damn cat.”

Above, the purpose of the ellipsis is to insert a dramatic pause reflecting how the quote was originally articulated. In this way, it serves to properly capture the intention behind breaking Rule #5.

Don’t use ellipses in formal writing. Only consider using them within quoted speech.

By the way, this punctuation post you're reading is a small part of my completely free handbook on Writing Well. Go read it to learn the full process of writing professionally, including identifying what's interesting to write about, building a consistent writing habit, and how to fully hook readers.

7. Avoid semicolons

It’s really easy to use semicolons [;] incorrectly, so my advice is to not use them in the first place. After all, semicolons are rarely needed to help communicate a point.

Since it would be pedantic to not at least provide you with one example of proper semicolon usage, I will show you the case where it’s difficult to misuse it: when you’re connecting two sentences that use different sets of words to express the same idea.

Correct: “She’s not a good listener; I feel like I’m talking to myself.”

Correct: “I can’t stop thinking about my dog; she is everything to me.”

Incorrect: “Those pants are gross; they smell bad too.”

Incorrect: “That person looks like a hamster; he’s weird.”

Notice how the correct examples use a semicolon to conjoin two sentiments that are essentially making the same point but from different perspectives. (Sometimes this is desired for the purposes of emphasis.) This is when you would use a semicolon.

In contrast, notice how the incorrect examples use a semicolon to conjoin two sentiments that convey complementary but not redundant information. “That person looks like a hamster” is one sentiment. “He’s weird,” although perhaps related in thought, is a separate sentiment. They are not mere rewordings. Do not use a semicolon here.

If we wanted to correctly use a semicolon for the last incorrect example, we could change the second part to, “That person looks like a hamster; he has rodent-like qualities.” In this way, we’re specifically describing what a hamster looks like instead of explicitly using the word “hamster.”

The primary takeaway from this rule is simple: Avoid using semicolons because they invite redundancy.  Redundancy is bad in writing. Find a way to express yourself concisely. Further, when a semicolon is used in this way, it can often be seamlessly substituted for a period. And a period is better than a semicolon because readers are more familiar with them and are therefore less likely to pause to assess why you're using a semicolon.

8. Only use colons for standalone sentences

Only use a colon when you’re presenting an example of what the words before the colon refer to:

Correct: “There is only one God: Thor.”

Correct: “She had one piece of advice: Never slap a monkey.”

Correct: “This is how you play footsie: with your feet.”

Correct: “He is a smart man: He solves sudokus in seconds, speaks many languages, and is great with chipmunks.”

There's also a second colon rule at work here: The words before the colon must be able to stand alone as a grammatically correct sentence. Meaning, if you replace the colon with a period, the words before the period make sense when read alone.

For example, below is incorrect colon usage:

Incorrect: “Her favorite color was: blue.”

Incorrect: “I love penguins because: they stand out.”

In these incorrect examples, the leading sentence couldn’t stand alone without adding words back in:

• “Her favorite color was” is not a proper sentence. The "was" ends the sentence mid-thought. It simply doesn’t sound right.
• “I love penguins because” also is not a proper sentence. "Because" is supposed to introduce a new thought, but doesn't.

In both of these incorrect examples, simply drop the colon and the sentence will magically read perfectly. (If punctuation serves zero grammatical purpose, don’t use it!)

The takeaway: Only use colons when your first sentence  introduces the second sentence, but the first sentence could stand alone if the next didn't exist.

9. Place ending punctuation inside quotation marks

American English dictates that punctuation (periods, exclamation marks, and question marks) should be placed inside quotation marks:

Correct: He said to me, “That’s one hell of a goat.”

Incorrect: He said to me, “That’s one hell of a goat”.

Correct: He asked, “Life sucks. Why am I so short?”

Incorrect: He asked, “Life sucks. Why am I so short”?

Correct: He yelled to the driver, “This isn't my Uber!”

Incorrect: He yelled to the driver, “This isn't my Uber”!

If you live in the UK, the rule is reversed: place the punctuation outside of the quotes.

10. Punctuate within full-sentence parentheses

If you’re wrapping a full sentence within parentheses, the final punctuation must stay within those parentheses:

Correct: John is reckless fool. (He'll die young.)

Incorrect: John is reckless fool. (He'll die young).

In contrast, if you’re wrapping merely a portion of a sentence in parentheses, leave the sentence’s ending punctuation outside the parentheses:

Correct: I’m going back home (Japan).

Incorrect: I’m going back home (Japan.)

11. Don't use exclamation marks outside of dialogue

Using an exclamation mark is like laughing at your own joke. — F. Scott Fitzgerald

Exclamation marks are distracting. Avoid them.

If you intend for a sentence to have vigor, make it blunt and concise. Then let readers read it however they're inclined to.

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This punctuation post you're reading is a small part of my completely free handbook on Writing Well. Go read it to learn the full process of writing professionally, including identifying what's interesting to write about, building a consistent writing habit, and how to fully hook readers.

Bonus: Vary sentence length

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