Hello! Download our free grammar guide here.

Would of? Could of? Should of?

Our Free Guide Gives You A Fun Way To Teach And Learn The Basics

Would of ? Could of ? Should of ?

Would of, could of, and should of are mistakes. Have you ever found yourself writing any of these?

Of and have sound similar when we say them out loud. This is especially true when we use the contractions would've, could've, and should've. Don't get tricked! Have (or 've) is the correct choice.


I would of called you, but I lost your number.

I could of danced all night.

I should of ordered a salad.


I would've called you, but I lost your number.

I could've danced all night.

I should've ordered a salad.

Why is of a mistake?

Would, could, and should are helping verbs that need to be a part of something called a verb phrase. Verb phrases are made up of one or more helping verbs and a main verb. Have can function as a helping verb. Of can't.

In our incorrect sentences, would, could, and should are followed by the word of, which is hopelessly trying to be a helping verb. But no matter how hard it tries, of is limited by its definition and function. The word that people mean to use here is the verb have.

"Of" is usually a preposition.
"Could of" is a mistake.

Verb Phrases

The verb phrases in our example sentences are would have called, could have danced, and should have ordered. Would, could, should, and have are helping verbs. Called, danced, and ordered are main verbs.

Verb Phrase

Helping Verbs

Main Verb

would've called

would, have


could've danced

could, have


should've ordered

should, have


If you want to learn more about how words like of and have work, our Get Smart grammar program will teach you. Watch the short instructional videos, diagram sentences, and enjoy learning how our language works. I'll make it really easy on you! I promise. 

"Should have" not "should of"
Elizabeth O'Brien from Grammar Revolution

If you don't want to teach or learn grammar by yourself,  click here to see how I can help you.

If you'd like me to help you teach or learn grammar in an easy and approachable way, check out The Get Smart Grammar Program. It lays everything out clearly and allows you to move at your own pace. Just watch the videos and complete your assignments. By the time you finish, you'll have an excellent grasp of grammar and sentence diagramming, and you'll feel much more confident. 

The Get Smart Grammar Program
The Beginner's Guide to Grammar Ebook

Our Free Guide Gives You A Fun Way

To Teach And Learn The Basics v

Download Now
Elizabeth O'Brien

Elizabeth O'Brien is the creator of Grammar Revolution.

Her lessons are guaranteed to give you more confidence in your communication skills and make you smile. :)