“Could of” or “could have”: which is correct?
The short answer
Always write could have, or the short form could’ve. Could of is never correct: it’s just how could’ve sounds when people speak quickly.
Spelling mistake
Why people get it wrong
In fast speech, have after a modal verb shrinks to a weak sound, /əv/. Said that way, could’ve sounds exactly like could of, so people who learned the phrase by ear write down what they hear.
The same thing happens with should of, would of, might of and must of. They are all mistakes for should have, would have, might have and must have.
The rule
Could have + past participle talks about the past. It describes something that was possible but didn’t happen (We could have taken a taxi, but we walked) or something we’re not sure about (She could have missed the bus).
Here have is an auxiliary verb, the same one as in I have finished. Of is a preposition, so it can never do that job.
How to remember it
Say the sentence with the full word have. If it still makes sense, have is the word you need: I could have helped works, I could of helped doesn’t.
Examples with could have
- I could have helped you if you’d asked.
- We could’ve caught the earlier train, but we wanted to sleep in.
- You could have told me the meeting was cancelled!
- She could have left her keys at the office.
- It could have been much worse.
Quick check
If I’d known about the party, I come.
After could, use have + past participle: I could have come.
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