Words at work

– 22 min read

99 most common grammar mistakes

Writer Team

The Writer Team

Does proper grammar seem daunting to you? Not sure if you should use the word “irregardless” or “regardless” in a sentence? Or how to use an infinitive verb?

The English language is finicky enough that a single missing comma can radically change the meaning of, well, everything you were trying to say:

Let’s eat friends! is more than a little creepy, while

Let’s eat, friends! sounds warm and inviting.

It’s our hope that this guide helps you avoid such blunders.

99 most common grammar mistakes in writing

One of the questions our subscribers ask most, whether they’re proofreading pros or full-time students, is how they can avoid the most common grammar mistakes. In this list, we outline some of the most common grammatical errors we’re seeing, based on millions of data points from Writer subscribers.

1. Let’s vs. Lets

Let’s not get carried away here — this one is pretty simple:

Let’s = let us. As in, let us not get carried away here…

Lets = to make something possible. This checklist lets you write better.

2. Its vs. It’s

It’s simple:

It’s = it is. As in, it’s so dang cold outside.

Its = associated with something recently mentioned. As in, the weather has a mind of its own.

3. Your vs. You’re

Your is a possessive pronoun that describes ownership of an item: your jacket is sweet!

You’re is the contraction of you are: you’re probably glad you have that jacket.

4. May vs. Might

May indicates a possibility; might indicates a hypothetical probability. I may quit my job — even though I’m good at it.

Then again, I might get fired.

5. Lay vs. Lie

Lay describes the action of placing something flat: lay down, Fido!

Lie describes the status of something resting flat: Fido likes lying (lie-ing) down.

6. Affect vs. Effect

Affect implies action: “I want to affect the world in a positive way,” said Jane. Effect describes its result. “The effects of your intention should be good,” replied her friend. Find out more about Affect vs. Effect here.

7. Too obvious?

Is this one too obvious, or not? Based on what must be billions of text-message bloopers it’s probably worth mentioning! Too refers to, well, too much of something / too many of something: “I have too much money to live in such a small house.”

It can also be used as a form of agreement: “yeah, I feel that way too.”

8. To vs. two

Two is a number (you know, this one: 2). ‘To’ is a word meant to be used in all sorts of different ways.

9. There vs. their

There refers to a location; their refers to a designation:

“See that restaurant over there?” – “Yep, that’s their favorite one!”

10. Their vs. they’re

They’re = they are:

‘They’re going to love that restaurant!’ – “Yeah, like I said it’s their fav.”

11. Loose vs. lose

Loose refers to something that’s been let out of control. While lose-ing is the opposite of winning! “Don’t be afraid to let loose. After all, what do you have to lose?”

12. Peek vs. peak

Peek means to look at something; peak refers to the top of something.

“Can I take a peek of the scenery?” – “Sure, but I heard the view’s better from the peak”

13. Peak vs. pique

We already mentioned what peak means. Just in case you were wondering, though, don’t confuse it with pique, which means ‘to stir up’ — “my interest was piqued.”

14. Compliment vs. complement

While both of these words refer to nice things, their meanings are quite different. A compliment is something nice you tell someone; complement refers to things that go well together.

Here’s a brain-bending compliment: “Your shoes complement your outfit so well!”

15. Piece of mind vs. Peace of mind

A piece of mind refers to one’s perspective or opinion: “My neighbor’s truck is so loud, it’s about time I gave him a piece of my mind!”

Whereas peace of mind refers to a mental framework: “Yeah…all that noise is really hurting my peace of mind.”

16. Literally

If you use the word literally, be sure to use it, well, literally! Watered-down words are no good for anyone.

17. To comma or not to comma

Commas are tricky little beasts. Sometimes skipping an oxford comma or two (even if using one would be grammatically correct) is actually a good call, so trust your instinct.

“Once upon a time, there was this really good writer…”

“Yeah I heard she didn’t always use commas.”

18. Semicolons

Semicolons are actually more like periods than commas. They usher in a new train of thought.

Semicolons are actually more like periods than commas; they usher in a new train of thought.

19. Semicolons + commas

Sometimes, though, semicolons are best followed up by a comma; in cases such as these, it’s totally okay to use them both!

20. Semicolons vs. commas

Many times commas work just fine by themselves, so don’t use semicolons if you don’t need to.

Many times commas work just fine by themselves; so don’t use semicolons if you don’t need to. (Doesn’t that look awkward?)

21. Parentheses and periods

Normally periods and other punctuation marks go after parentheses (normally).

22. Periods inside parentheses

The exception is if you’re writing an entire sentence within parentheses — like the example in mistake #20 above.

23. Quotation placement

“Periods, commas, question marks, exclamation points, quotations within quotations, etc. should always be placed inside quotation marks,” he explained.

24. Unless you’re outside the United States

That’s right: in most other countries, punctuation marks actually go outside quotations. Go figure.

25. Plural or singular!

It really don’t sound good if you doesn’t stay consistent with plural and singular forms…

26. Hyphens vs. dashes

A hyphen, like the one to the right, connects two or more inter-related words — a dash, like the one just to the left, connects two or more related thoughts.

27. En dash or Em dash?

An en dash is about the width of the letter “N,” and it’s meant to show a range, like 1-10.

An em dash is longer — it’s meant to facilitate those fun connections we mentioned earlier.

28. Inappropriate hyphens

In general, don’t use hyphens to connect two parts of one word. The way we spelled ‘inter-related’ up there? Yeah…that’s incorrect. Unless you’re trying to prove a point.

29. Missing dashes

On the other hand, don’t rule out the use of hyphens entirely. They can be insanely-awesomely-silly-ly useful!

30. Don’t be too negative

Actually, forget that — be positive. After all, why negate a negative when you can present a positive instead?

31. The other kind of double negative…

Ever feel like you can’t do nothing right? Maybe like you can’t spell nothing correct at all? Please, don’t ever write like this. Unless you’re authoring a Southern-twanged novel or something.

32. Dot-dot-dot

Some people like doing dots like this…

Others like this method . . .

But feel free to use whatever resonates most with you.

33. Dash spacing

And some people don’t like having spaces around their em dashes—they can get pretty particular about it. Best-selling author Tim Ferris leaves spaces around his, though — so apparently it doesn’t matter too much.

34. 50 cent(s)

This is like the mathematical version of the double-negatives we mentioned earlier. If you’re trying to denote a certain number of cents, either write out the full decimal, or list the number of cents:

50 cents, or $0.50

Don’t do both: $0.50 cents

…unless, of course, you really are talking about half of one cent…

35. The issue of marriage

In this case, marriage is only an issue if the term is used incorrectly:

“She was married with a football player.”

Saying “she was married to a football player” just sounds way better.

36. Each and every student

The term “every” almost always goes with a singular noun:

“Every student passed the test” is correct, while “every students passed the test” is not.

37. Although/but

The words although and but don’t often work well together. Try to use one of them or the other, not both!

Although it was raining, we still went outside.


It was raining, but we still went outside.

38. You and I

“Pam and me went to get some groceries” is incorrect;

“Pam and I went to get some groceries” is spot on.

39. Amount vs. number

‘Amount’ should be used for something uncountable: “a large amount of dirt.”

‘Number’ should be used for things you can quantify: “a large number of people.”

40. Fewer vs. less

‘Less’ should be used for something uncountable: “less dirt.”

‘Fewer’ should be used for things you can quantify: “fewer people.”

41. Shared possessions

If you’re sharing something, then it’s enough to use one apostrophe: This is Tim and Andy’s house.

42. That’s all well & good…

“I slept well” is correct; “I slept good” makes it sound like you need a little more sleep.

43. Or is it good & well?

If you’re describing the quality of something, however, ‘good’ can be a very good fit.

44. The police is coming!

Actually, the police are coming. Unless this is also part of that slang-infused novel you’re writing.

45. A vs. an

Do you have an idea of whether or not this sentence is grammatically correct? Hint: it is!

46. Amicable/amiable

‘Amicable’ should be used to describe pleasant meetings and such; ‘amiable’ should be used as a synonym for ‘kind.’

47. Write vs. right

This article is meant to help you write…the right way.

48. Beside/besides

“Want to sit beside me?” is more correct than “want to sit besides me?”

49. Farther/further

“Want to bike a little farther?” is more correct than “want to bike further?”

50. Can vs. may

‘Can’ implies an ability; ‘may’ implies a possibility.

51. Since/for

I’ve been in Europe for 3 weeks. I’ve been in Europe since the first. If you try swapping ‘since’ and ‘for’ in the above sentences, it just doesn’t work.

52. No one vs. anyone

“He didn’t know nobody” is incorrect; “he didn’t know anyone” is much better.

53. More smart, or smarter?

If you want to sound smarter, try to avoid talking about being “more smart” than others!

54. A lot/alot

Did you know that ‘alot’ isn’t a word? Use ‘a lot’ instead

55. Alot/Allot

Unless, of course, what you’re really trying to say is ‘allot,’ a word which means “to give or assign.”

56. Wreck vs. wreak

The wreck wreaked havoc on several of the cars involved.

57. Pore vs. pour

A pore is a small opening; a pour is what’s done to a drink!

58. Ran vs. run

“I ran fast” and “I run fast” are both correct, but they do have slightly different meanings. If you’re still pretty quick, use the ‘run’ version.

59. Suppose so?

You’re supposed to use ‘suppose’ in the above type of situation.

60. Collocations

Some words just go better together. “Due to the fact that” is one prime example. If you use collocations like these, don’t try to divide them up!

61. Got know-how?

“I know how to write.” “I’ve got business writing know-how.” While both of these sentences are grammatically correct, one is much less awkward than the other.

62. Keep tense consistent!

“I went to the grocery store and buy some eggs.” → See how improper that sounds? Make sure you keep your tense consistent, whether it’s past or present or future tense you’re talking about.

63. Unless you’re talking about something universal…

If you’re talking about a timeless truth, though, you can switch your tense up a little:

“‘The earth revolves around the sun,’ his parents explained.”

64. Seniority

“He’s senior to me” works, and so does “he’s older than me”…but don’t try to flip these around: “he’s senior than me” and “he’s older to me” are both wrong.

65. Neither/nor

‘Neither’ and ‘nor’ go great together: “She was neither stronger nor faster, but she was still a great athlete.”

66. Cardinal vs. ordinal

Cardinal numbers deal in absolutes; this is grammar mistake #66. Ordinal numbers deal with positions; this is the 66th grammar mistake listed.

67. Spell it out

Typically numbers under 10 should be spelled out, though there may be one or two valid exceptions to this rule.

68. Missing articles

Don’t forget to put the word ‘the’ before appropriate items: the book, the blog, the article, and so on.

69. One should stay consistent

If you’re speaking about another person, use consistent pronouns: “One should stay consistent when they are writing” sounds much better than “one should stay consistent when he is writing.”

70. Hard vs. hardly

“Writing is hard.” → Correct

“Writing is hardly hard when you use Writer.” → Also correct!

71. Hardly vs. hardy

“Carrots are very hardly vegetables.” → ??

“Carrots are very hardy vegetables.” → Correct.

72. First come, first served?

Though most people (i.e., restaurants) will say “first come, first serve,” what makes much more sense is “first come, first served.”

73. Shoulda woulda coulda

‘Should of,’ ‘would of,’ and ‘could of’ are actually all incorrect, though they might sound decent enough.

The proper usage, of course, is ‘should’ve,’ ‘would’ve,’ and ‘could’ve.’ These are contractions for “should have,” “would have,” and “could have.”

74. Wait, so you could or couldn’t care less?

Many people use the phrase I could care less’ to describe something they don’t really care about. If you think about it, though, what they’re trying to say is that they couldn’t care less.

75. “I” shouldn’t come last

“At the restaurant, it was just her and I” just doesn’t sound as good as “At the restaurant, it was just me and her.”

76. But “me” shouldn’t come first

The above writing mistake also has an inverse:

“Me and her went to the restaurant” just doesn’t sound as good as “her and I went to the restaurant” — but that’s not right, either. Why? Because if you take away “I,” the sentence would read “her went to the restaurant.“ The correct usage is “She and I went to the restaurant.”

77. Apostrophe calamity

The Johnson’s. The 70’s. The Jones’s…life is simpler without all these apostrophe’s!

For plurals, try the Johnsons, the 70s, and (if you’re trying to keep up with them) the Joneses instead. But if the Joneses own something, it’s the Joneses’ (see number 93).

78. Mmm, expresso

While ‘expresso’ might sound correct to some, it’s actually spelled ‘espresso.’ Just FYI.

79. A sleight of hand

That’s right: a ‘slight of hand’ is actually incorrect!

80. Forte, niche, and other mispronunciations

Forte’s pronunciation = fort.

Niche’s pronunciation = neesh.

Just don’t spell either of them that way…

81. Exact revenge!

If you must have your revenge, don’t extract it, exact it!

82. Soggy appetites

“That really wet my appetite.” → Incorrect

“That really whet my appetite.” → Correct

83. Do your due diligence

See what we did there? It’s ‘due diligence,’ not ‘do diligence.’

84. Per say

‘Per se’ is a Latin phrase meaning ‘in itself’…per say is how you pronounce it.

85. Worse comes to worst

While we’ve all heard the phrase “if worse comes to worse,” it doesn’t really make sense unless “worse” goes all the way to “worst.”

86. Chalk it up…

…don’t “chock it up.”

87. Free rein

To give “free rein” to something means to let go of control.

To give “free reign” implies kingship without effort.

88. Nip it where?

In the bud, not in the butt! For those unfamiliar, this phrase’s literal meaning refers to nipping flowers in the bud.

89. Disinterested vs. uninterested

These two terms aren’t actually synonyms. Being disinterested implies that you couldn’t care less; being uninterested means you care enough to turn your interest away.

90. Nauseous vs. nauseated

Don’t worry: almost everyone gets this one wrong. “Nauseous” technically means to be capable of making others nauseated; “nauseated” means not feeling well.

91. The impact of impactful

Is impactful a word? Contrary to what you may have heard, it is — so don’t let people tell you otherwise.

92. However vs. nevertheless

Fans of classic grammar will insist that sentences shouldn’t be started with “however,” at least not when they can be started with “nevertheless” instead. We’d say use whichever sounds better to you.

93. Too many s’s

When in doubt, drop the extra s. Arkansas’ is usually preferred over Arkansas’s, for example.

94. Run on sentences

Contrary to popular belief run-on sentences aren’t necessarily long they simply occur when commas and/or other types of punctuation are missing like this.

95. Too many commas

Using too many commas, on the other hand, isn’t good either, because it can reduce the casual flow, from word to word, that you should strive for.

96. A break from parallel

“He was studying math, science, and digital photos” might not sound that bad, but why not say, “he was studying math, science, and digital photography” instead?

97. Sentence splice

I wanted to cook a great dinner, however I was just too tired.

I wanted to cook a great dinner; however, I was just too tired.

I wanted to cook a great dinner. However, I was just too tired.

The first of these three sentences is incorrect. Why? Because it’s spliced together without the appropriate punctuation.

98. Misplaced semicolons

On the other hand; using semicolons where they’re not needed (say, in place of commas) isn’t good either.

99. Incorrect capitalization

You probably know to capitalize proper nouns and the first word of each sentence. But sometimes you also need to capitalize after a semicolon or the first word of a quote.

Christine explained, “Community is key to building a successful online business.”

7 major types of grammatical errors

Bad grammar can make a poor first impression, whether you’re writing a business email or messaging a potential date. People tend to make assumptions about your abilities based on how you communicate. If you’ve made it this far and want to learn how to write better, let’s look at some examples of bad grammar.

Verb tense errors

One of the most common grammar mistakes is using the wrong verb tense. The verb tense tells your reader when the action takes place: in the past, present, or future. When writing anything, you want to be consistent on verb tense unless there is a good reason to switch tenses.

The mistake: I drive to the store and I bought shoes.

Why it’s wrong: A verb tense shift happens when the writer changes tense in a sentence or paragraph. In this case, drive is present tense and bought is past tense.

The correction: You should change drive to drove, or change bought to buy to make the sentence correct. Be mindful of shifting tenses within a paragraph.

Subject-verb agreement

The subject of the sentence (the person or thing doing the action) and verb (the action) in a sentence must agree with each other. If the subject of the sentence is singular, the verb must be singular. If it’s plural, the verb must be plural also.

The mistake: Michael and Sue is going to the beach.

Why it’s wrong: “Michael and Sue” are plural. The auxiliary verb “is” is singular, which is a lack of agreement.

The correction: The sentence should read, “Michael and Sue are going to the beach.”

Comma splice

A common punctuation mistake is the comma splice. A comma splice happens when two separate sentences take place rather than using a period or semicolon.

The mistake: I went to Steve’s house, and ate lunch.

Why it’s wrong: Writers often use a comma splice when they connect two independent clauses with a comma rather than a comma and a coordinating conjunction.

The correction: Use commas to separate two independent clauses when they are joined by coordinating conjunctions: and, but, or, for, so, yet. In the compound sentence above, “and ate lunch” doesn’t have a subject, so you don’t need to add a comma before “and”.

Small punctuation errors like this seem like a small thing, but punctuation helps guide readers through your text smoothly. You can use a punctuation checker to double check your work and correct these grammar errors in minutes.

Misplaced or dangling modifiers

misplaced modifier is a word, phrase, or clause that is separated from the word it modifies or describes. A dangling modifier is a grammatical error where the modifying word is too far away from the subject of the sentence, or there is no subject.

Sentences with these mistakes often sound awkward or confusing. But don’t worry, misplaced and dangling modifiers are common writing mistakes and even trouble the experts in English grammar.

The mistake: Disappointed, the story took me forever to write.

Why it’s wrong: The modifier should be as close as possible to the thing it modifies. Since the subject of the sentence is disappointed (not the story), the sentence should have the speaker and modifier closer.

The correction: The sentence should read, “I was disappointed by how long the story took me to write.”

Overuse of adverbs

An adverb is a word that describes a verb—they often end in -ly. Writers use adverbs to give more information about the verb and make it more descriptive. Using adverbs every so often isn’t bad grammar, but too many can mean poor verb choices.

The mistake: The wedding went really bad.

Why it’s wrong: The adverb “really bad” modifies the verb “went”. While “really bad” gets the point across, does it really paint a picture for the reader?

The correction: Use a more descriptive sentence like “the wedding was a disaster” instead.

Passive voice

English grammar experts and teachers consider passive voice a bad writing habit. With the passive voice, the object of the action becomes the subject of the sentence. It’s recommended to turn passive constructions into active voice, where the subject does the action of the verb in a sentence. Active voice can make your writing stronger and more direct.

The mistake: The car was driven by Chris.

Why it’s wrong: The last words in the sentence “by Chris” make up a preposition that tells the reader who is performing the action. Even though Chris is performing the action, he is not the subject of the sentence. You could remove him from the sentence entirely using passive voice.

The correction: The active voice construction would be “Chris drove the car”.

Sentence errors

Sentence structure mistakes are one of the most common grammatical errors. You can break down sentence errors into three categories: sentence fragments, run-on sentences, and overloaded sentences.

Sentence fragments

Sentence fragments are clauses that miss one of the following elements: a subject, a verb, a complete thought. You often miss fragments because they are no big deal in spoken grammar, aka conversation, but can make a big impact on your writing’s clarity.

The mistake: He still loved his parents. Despite everything that had happened.

Why it’s wrong: The second sentence “despite everything that had happened” has no subject or verb. You depend on the first sentence to give the second one meaning.

The correction: The complete sentence for this clause is “Despite everything that happened, he still loved his parents.”

Run-on sentences

Run-on sentences, also known as fused sentences, happen when two complete sentences are brought together without any punctuation or conjunction, such as a semicolon or period. Run-on sentences don’t have to be long to be considered grammatically incorrect.

The mistake: Yesterday was the best day ever my family and I began our ski vacation.

Why it’s wrong: There is more than one idea communicated by two independent clauses.

The correction: Yesterday was the best day ever! My family and I began our ski vacation.

Overloaded sentences

An overloaded sentence is one that squashes too much information together and, as a result, becomes hard to understand for readers.

The mistake: Youth league coaches need to understand that the education of a child is a big undertaking and should be done with care and consistency so that the child can gain maximum benefit from each training in order to set a solid foundation for any follow-up teaching.

Why it’s wrong: A good sentence focuses on one idea. The example above wanders around and takes too much mental effort before understanding the point.

The correction: Youth league coaches need to understand that the education of a child is a big undertaking. It should be done with care and consistency. That way, children can get the most from each training and set a solid foundation for any future teaching.

Related reading: An Introduction to AI Writing Software

Lowering the number of grammar mistakes in your writing

They say rules are meant to be broken — and we’d agree, as long as one is talking about the core grammar rules. Sometimes a missing comma or random sentence splice can make good writing great! So don’t be afraid to follow your intuition. If you’re having fun, chances are your reader will be, too.

(For the words that matter most, take no chances! Make sure you’re using Writer.)

Common grammar mistakes FAQ

What is a grammatical error?

A grammatical error refers to an occurrence of faulty, unconventional or controversial usage, such as a dangling modifier or possessive noun errors. Grammar errors are also called usage errors.

What are examples of grammatical errors?

  1. Verb tense errors
  2. Faulty sentence structures
  3. Punctuation mistakes
  4. Overuse of adverbs
  5. Passive voice misuse
  6. Dangling participles

How do you identify grammatical errors?

You can identify grammatical errors by using a grammar checker to find and fix errors, improve word usage, verb tense, and punctuation for English text.

What are the 10 most common grammar mistakes?

Using millions of data points from Writer subscribers, we identified 10 common grammar mistakes:

  1. Let’s vs. lets
  2. Its vs. it’s
  3. Your vs. You’re
  4. May vs. Might
  5. Lay vs. Lie
  6. Affect vs. Effect
  7. To vs. two
  8. There vs. their vs. they’re
  9. Loose vs lose
  10. Peek vs. peak

What are three most common sentence errors?

  1. Run-on sentences
  2. Sentence fragments
  3. Overloaded sentences