Knew vs. Known
“Knew” and “known” are different forms of the irregular verb “know.” “Knew” is the simple past, while “known” is the past participle used in perfect constructions.
Use “knew” for the simple past and “known” as the past participle, especially after have/has/had.
Key details
Choose the right form
| Meaning / situation | Form / construction | Decision |
|---|---|---|
| simple past | knew | Use “knew” for a completed past-time verb. |
| past participle | known | Use “known” with have/has/had or in participial/passive structures. |
Quick tests
Meaning / construction test
Does the form follow have, has, or had (or function as a participle)?
If yes: Use “known.”
If no: For the simple past, use “knew.”
Caveat: “Known” can also function adjectivally; this guide focuses on the verb forms of “know.”
Examples
I knew the answer yesterday.
Simple past takes “knew.”
I have known her for years.
The perfect construction requires the past participle “known.”
The problem was known to the team.
The participial/passive use takes “known.”
Further guidance
Core difference
“Knew” is the simple-past form of “know”; “known” is the past participle used with auxiliaries such as have, has, or had.
Fast Test
If have, has, or had directly governs the form of “know,” choose “known.” For a standalone finite past-tense verb, choose “knew.”
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- know — Cambridge Dictionary (opens in a new tab)Cambridge Dictionary · Cambridge lists knew as the past tense and known as the past participle of know.