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What’s the Difference Between “Based Off” vs. “Based On”?

Updated on October 10, 2023Grammar

Is it based on a true story or based off of a true story? You’ve probably heard people use both and may have seen them used interchangeably at the beginning of movies inspired by real-life events. So is it based on or based off?

Based on is the correct choice between the two in writing, though the phrase based off of could also be used in conversation and informal communication. We’ll explain the difference between the two, why based on is preferred by most writers, and provide examples of how to use both phrases.

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What is the difference between based on and based off?

Based on and based off (often extended to based off of) means that something is formed or developed from a fact or event. Based on is the preferred phrase in academic writing and British English, while based off of is seen more in spoken American English.

According to the Chronicle of Higher Education, based on is the more popular choice between the two, especially in writing, though based off of has grown in popularity.

Regardless, there’s nothing wrong with using either based on or based off of during a conversation or even in your writing. So unlike other tricky English words, both are grammatically correct. Some people prefer based off of because it sounds more casual than based on.

What is the meaning of based on?

Based on means that something has a basis that’s formed or developed by a fact, opinion, or event.

The word based is an adjective that describes a noun as having a foundation or roots in something else. A California-based company is a company that has its headquarters in California.

A base can also be something that is underneath another thing, which is why on is the preferred preposition to use. If we’re saying that something is based on something else, we’re saying it’s on top of the base.

Use based on when you want to say that two things are closely related or linked. For example, a filmmaker working on a World War II movie would say their film is based on a true story. A detective could say they solved a case based on evidence or testimony gathered during their investigation.

What is the meaning of based off of?

Based off of means the same thing as based on—something is rooted in a fact, belief, or event.

Based off of is grammatically correct because the preposition of takes the place of on. Saying something is based off something else is grammatically incorrect because you’re saying that you’re not on that base, so you need of to connect the two clauses.

Some people argue that based off of means that a movie, book, or other project may borrow facts from real-life events but is mostly fictional. In other words, a movie could be based off of a person who existed but contains events that never happened. On the other hand, a movie based on the same person would be more accurate. Both phrases are still accurate and can be used interchangeably.

What is the meaning of based off?

Based off should only be used in informal conversation and should be avoided in writing because it’s grammatically incorrect. Let’s clear up this commonly confused word.

Remember that based is an adjective that means something has a basis or roots in something else. Based off would imply that you’re off that base, so there’s no connection between the two things you’re trying to connect.

Adding the preposition of groups the two clauses together and works in place of the preferred preposition on.

Based on and based off of examples

Here are three examples of how to use based on in a sentence.

  • This movie is based on a true story.
  • My thesis is based on hours of research on Shakespeare’s plays.
  • Your assignment is to write a story based on a childhood experience.

Here are three examples of how to use based off of in a sentence.

  • The dance is based off of an Irish jig.
  • Based off of my interviews with the suspect, I believe he’s innocent.
  • This recipe is based off of a casserole my grandmother would make every Sunday.
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