Is it could of or could have?
The correct phrase is could have, not could of. People sometimes accidentally write “could of” because it sounds like the contraction “could’ve.” However, the preposition “of” never goes after the modal verb “could.”
“Could have” and “could’ve” are both correct ways to show that something was once possible but didn’t happen (e.g., “We could have/could’ve gone to the beach last year, but we went to the mountains instead”).
To avoid mistakes like “could of,” “would of,” “should of,” etc, you can run any piece of writing through the QuillBot Grammar Checker. It will instantly spot these errors and show you what to write instead.