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Common Grammar Mistakes You Need to STOP Making

avatar Accelerate Media | Staff Piece

This post was originally published January 22, 2018 and was updated April 4, 2022.

Good grammar and writing are essential in the workplace. Whether it’s emailing a coworker, typing a proposal, or constructing a blog post for your company, it’s imperative that you get your point across in a professional, intelligent manner.

However, so many people still continue to make common mistakes while writing. Some mistakes are harder to spot and we may not see them as often. Others, we tend to notice right away.

This list is here to help you avoid these common grammar mistakes in the future.

Fewer vs. Less

While both words mean a smaller amount of things, they have different meanings.

“Fewer” should only be used when something is countable or if you’re referring to people or things in plural.

Ex: People are buying fewer houses these days.

Ex: Fewer girls are studying computer science.

Use “less” when you refer to something that cannot be counted or doesn’t have a plural. “Less” is also used with numbers when they are on their own and with expressions of time or measurement.

Ex: I spend less time on the computer than I used to.

Ex: My parents are less than 2 hours away.

Affect vs. Effect vs. Impact

In everyday speech “affect” is a verb, meaning to influence or produce a change in something.

Ex: How does too much candy affect children?

“Effect” is a commonly used noun, like the result of an outcome. When you add an “s” to the end of it, making the word “effects” it changes the meaning entirely to now refer to personal belongings.

Ex: The effect of the medicine on his illness was immediate.

Ex: In his will, he left all of his personal effects to his wife.

“Impact” is sometimes mistakenly used to replace either of these words in a sentence if the writer is confused about which to use. While doing so may make the sentence seem correct, “impact” should really only be used when describing a collision. 

Ex: The impact of the car crash totaled his car.

Ex: The ball impacted the bat with a loud noise.

Bottom line: Don’t cop out and use “impact” unless you’re describing a crash; otherwise, use “affect” or “effect.” 


Eastern Daylight Time (EDT) and Eastern Standard Time(EST).

After you spring forward, you’re in daylight time (EDT), around March- November. Once you fall back, you’re in standard time (EST), which is roughly December through February.

Ex: If you wanted to set up a meeting with a client in December you would set it up for 1:00 PM EST

Ex: If you wanted to set up a meeting with a client in July you would set it up for 1:00 PM EDT

Then vs. Than

“Then” is used with a certain period of time.

Ex: First we went shopping, and then we got lunch.

“Than” is comparing one thing with another.

Ex: I am much better at soccer than my sister.

Principal vs. Principle

“Principal” is a noun referring to someone who holds a position or rank above everyone else. It can also refer to capital or property before interest.

Ex: The principal will see you now.

“Principle” is only a noun. It refers to a rule, assumption, basic truth, or law.

Ex: It’s the principle of the matter!

Complement vs. Compliment

“Complement” refers to something that pairs well with something else, sometimes thought to be complete or perfect it.

Ex: That shade of lipstick complements her complexion.

A “compliment” is an expression of praise, regard, or thanks.

Ex: Person A: “I love your dress!”
Person B: “Thank you! And thanks for the compliment.”

These are just a few grammatical errors we’ve seen people make frequently. Have you noticed your coworkers making mistakes similar to these?