Have you ever been in a situation where you don’t know the proper grammar? I know I have.

It’s more common than you might think. There are over 30 grammar mistakes one can make, which include both spoken and written errors.

Because these mistakes are so common, especially written ones, we decided to create a cheat sheet of the most common grammatical slips to help writers, employees, and anyone else who needs a bit of assistance.


For titles, Title Capitalization recommends capitalizing words with more than four letters, and the first and last words of the title. They also suggest capitalizing all nouns, pronouns, verbs, adverbs, adjectives, and subordinate conjunctions. The definitions come from Merriam-Webster.

  • Nouns: the subject of a sentence, which can “refer to an entity, quality, state, action, or concept”
  • Pronouns: a set of words (she, they, etc.) that replace a noun
  • Verbs: words that “expresses an act, occurrence, or mode of being”
  • Adverbs: words that serve as modifiers “expressing some relation of manner or quality, place, time, degree, number, cause, opposition, affirmation, or denial”
  • Adjectives: words that modify nouns, which “denote a quality of the thing named, to indicate its quantity or extent, or to specify a thing as distinct from something else”
  • Subordinate Conjunctions: words, like because or although, that link “a main clause and a clause which does not form a complete sentence by itself”


Some people debate whether or not to capitalize words after using a colon. According to The Punctuation Guide, words should be capitalized if there are two or more sentences after the colon and if the word is a proper noun.

Only capitalize words following semicolons if the word is a proper noun.


Periods are the most common of the punctuation marks; therefore, they have the most rules associated with them. In most situations, it is best to use a period.

  • With multiple punctuation: Periods are unnecessary if the sentence already ends in a question mark, exclamation point, or another period. (He works for Starbucks Inc.)
  • With indirect questions: Also known as paraphrasing, these sentences use a period. (She asked me what time it was.)
  • Where part of the sentence is in parenthesis: In these situations, the period will be outside of the parenthesis. (She works for National Aeronautics and Space Administration (NASA).)
  • Where the whole sentence is in parenthesis: In these situations, the period is inside of the parenthesis. (This is an example sentence.)


Question marks end sentences that contain questions or have uncertainty in them.

  • With direct questions: These sentences also contain quotation marks and end in question marks. (Where do you work?)
  • Editorial review: Inserted by a third party, used to express unclear messages or incorrect information. (In 2010(?) 2011(?), this company opened.)
  • As part of a title: If the title contains a question mark, keep the question mark in the sentence. (Ashton Kutcher stars in Dude, Where’s My Car?)


Exclamation points show strong, positive emotions such as excitement and surprise. In order to keep this purpose, they should only be used in moderation, and in these circumstances.

  • At the end of a sentence: In instances of exclamatory sentences, some people believe they need both a question mark and an exclamation point, but only the latter is needed. (What are you doing here!)
  • With direct quotes: Contrary to quotes that end in periods, if a quote ends in an exclamation point then the exclamation point is used instead of a comma to separate the quote from the person who said it. (“Home run!” the announcer screamed.)
  • As part of a title: If the title contains an exclamation point, it should remain there. (My favorite musical is Oklahoma!)


Commas, Colons, and Semicolons 


There are many situations and sentences that require commas, and for that reason, there are several opportunities for mistakes.

  • Separating three or more items in a list (I need to buy soap, toothpaste, paper towels, and napkins from the grocery store.)
  • Separating two independent sentence clauses that are connected using coordinating conjunctions like “and,” “yet”, “for”, “but,” “or”,” “nor,” or “so” (I was late to the football game, so I missed the kickoff.)
  • Seperates dis-similar adjectives from one another (I ordered a large, cool glass of iced tea).
  • Separating an introductory word, such as “although”, “while”, “however”, “when”, and “after” from the rest of the sentence (After, we went to a movie.)
  • Seperates a quote from the person who said it (“That’s not very polite”, she told him.)


Another sticky situation with commas is the Oxford comma. When using the Oxford comma, a comma is added between the last and second to last items of a list.

  • With the Oxford comma: My favorite ice cream flavors are chocolate, birthday cake, chocolate peanut butter, and coffee.
  • Without the Oxford comma: My favorite ice cream flavors are chocolate, birthday cake, chocolate peanut butter and coffee.


Your use of the Oxford comma is up to you and your business’ style guide. However, APA Style (American Psychological Association) does recommend use of the Oxford comma.


Colons (:) are not as commonly used as commas, but are still easy to use incorrectly.

  • Between two independent clauses in which the second clauses further explains the first. (I have two dogs: their names are Spot and Lucky.)
  • Formatting lists. (I need the following fruits: pineapple, cantaloupe, banana, and orange.)
  • Illustrating ratios, time, and page references. (It is 9:05 am.)
  • Placing emphasis on a certain word or phrase. (She finally found her calling: teaching)



Semicolons (;) can be confused with both commas and colons; however, they have their own rules and times of use.

  • Connecting two independent clauses where there are no coordinating conjunctions. (She decided to go to Michigan State; go green.)
  • Creating lists with internal commas. (Paper towel, bleach, and trash bags are in aisle one; soda, chips, and salsa are in aisle two; frozen dinners, ice cream, and milk are in aisle 3.)
  • Connecting two independent clauses that are linked with a transitional expression like “consequently”, “for example”, “so”, “thus”, “nevertheless”, or “accordingly”. (My dad is an expert bowler; for example, he bowled a perfect game on Tuesday.)


Bolding, Italicizing, and Underlining


Use bold for small stretches of text and as little as possible. When using bold, it is to place emphasis on the bolded words.

Bold can also be used to distinguish between different sections in a blog post or paper, and is used on headings.


Words in foreign languages, usually ones that are relatively uncommon, may be italicized.

According to the Purdue Owl, titles of books, academic journals, magazines, newspapers, films, TV shows, long poems (similar to the length of a book), plays, operas, works of art, musical albums, and websites.


Purdue Owl writes that underlining is most often used when writing by hand when italics and bold are not options.

However, there are times when it is beneficial to underline words in a blog post. Go Blogging Tips suggests underlining when defining words, linking to outside sources, and for highlighting keywords.

Parenthesis and Brackets

Parenthesis ( ) are used as a way to include relevant information that helps provide clarification for the sentence. However, information enclosed in the parenthesis is not a part of the subject, and should not have an impact on the verb. In most cases, commas will come after the use of the parenthesis.

  • After thinking about the question (for about a minute), I realized I did not understand the question being asked.


Brackets [ ] cannot be used interchangeably with parenthesis, and are used only within quotations.

  • Added by a third party, and used to further explain the quote. (“My dad gave it [the car] to me.”)
  • To mark a confusing part of the sentence or grammar/spelling error, where the word “sic” illustrates someone’s direct quote. (“What do you think your [sic] worth?).”


Hyphen and Dashes 


A Hyphen (-) creates and shows compound words. When deciding whether a hyphen is necessary, think about if the meaning would be unclear without combining the words. Some examples of compound words include high-risk, eye-opener, and follow-up.

En Dash

The En Dash (–) is slightly longer than the hyphen, and has a couple of different uses. Additionally, the en dash could be spoken aloud or rewritten as either “to” or “through”.

  • Showing a range of numbers: The en dash represents a set of numbers. (The professor assigned pages 25–46 as homework.)
  • Reporting scores: Similar to the previous instance, the en dash announces scores or contest results. (The green team beat the blue team 21–15).
  • Representing conflicts, connections, or directions: (This flight flies Amsterdam–Florence.)


Em Dash

The Em Dash (—) is the longest of the three and is the most versatile. Because of its versatility, the em dash can replace commas, parenthesis, or colons. Em dashes do not require spaces between them and the words (both before and after the dash).

  • Replacing commas: The purpose of exchanging a comma for an em dash is to increase the readability of a sentence.
  • Replacing parenthesis: In this case, use the em dash to bring attention to the part of the sentence inside of the em dashes. (After enough people got sick—150, to be exact—the company recalled the chicken.)
  • Replacing colons: The em dash places emphasis on the conclusion of the sentence. (I finally went to the grocery store—three hours later than I planned.)
  • Cases with two em dashes: Use two em dashes to signify missing letters in a word. (The paper ripped, so we only saw part of the word, “al——“.)
  • Cases with three em dashes: Use three em dashes when a whole word is missing from a sentence (The police officer arrested a man named ———.)



Homophones are words that sound alike, but have different spellings and meanings.

Than vs. Then

  • Than: Used to compare two or more items (I would rather eat pasta than pizza.)
  • Then: Shows an action or event following something else (I went to work then to the grocery store.)


You’re vs. Your

  • You’re: A contraction of the words “you” and “are” (You’re my best friend.)
  • Your: Shows possession of an object by a single person (Your coffee is ready.)


To vs. Too

  • To: Describes an action, a recipient, or a location (I’m going to the dentist.)
  • Too: A synonym for also or shows excess (It’s been too cold recently.)


There vs. Their vs. They’re

  • There: Used to describe locations or places (There is our exit.)
  • Their: Shows possession of an object by a group (Their house computer is an Apple.)
  • They’re: A contraction of the words “they” and “are” (They’re the best at trivia.)


Effect vs. Affect

  • Effect: A noun that usually shows a result or change (The car accident had a terrible effect on me.)
  • Affect: A verb which influences something else (The audience was affected by his speech.)


It’s vs. Its

  • It’s: A contraction of the words “it” and “is” (It’s my favorite flavor.)
  • Its: Shows possession (The milk is past its expiration date.)


A lot vs. Allot

  • A lot: Used to show excess (A lot of people celebrate Christmas.)
  • Allot: Quantifies numbers or time (We can allot 20 employees for the job.)
  • PS, “alot” isn’t a word.


Who’s vs. Whose

  • Who’s: A contraction of the words “who” and “is” and is used for living beings (Who’s working tonight?)
  • Whose: Shows ownership of an object (Whose sweater is this?)


Into vs. In to

  • Into: Shows movement. (The student walked into the library.)
  • In to: Used when “in” is an adverb and “to” is the preposition (The doctor ran in to save the patient.)


Other Confusing Words

Me vs. I

  • The best way to judge this is to take the other person out of the sentence. If the sentence sounds correct using I, use I. If it sounds correct using me, use me.
  • My boss sent Bill and me an email that night; my boss sent me an email that night.
  • Jason and I have dated Emily; I have dated Emily.


Who vs. That

  • Who: Describes a person. (I was the person who chose the restaurant.)
  • That: Describes an object. (She has a computer that is always breaking.)


Between vs. Among

  • Between: Helps to differentiate words that are separate. (He was sitting between Tom and Jim.)
  • Among: This word is used to specify words that are not separate because they are part of a group. (We divided the money among the three of us.)


Farther vs. Further

  • Farther: Measures physical distances. (Chicago is farther away than Detroit.)
  • Further: Used to indicate metaphorical distances. (We drifted further apart.)


Fewer vs. Less

  • Fewer: Used in sentences where the number can be counted or where objects can be plural. (Joe had fewer toys than Sally.)
  • Less: Used in sentences where the numbers cannot be counted and with objects that are only singular. (I have less time now that I have graduated.)


Much vs. Many

  • Much: Placed in front of collective or singular nouns. (Much of the report is true.)
  • Many: Used in front of plural nouns. (She has many friends.)


These are some of the most common grammar mistakes, but this is not an all-inclusive list. (In fact, no post about grammar is every truly complete, especially with language constantly evolving.) We hope this has given you a better idea of the correct usage of words, punctuation, and fonts, and can serve as a reference page to if you’re in need of a refresher.