Knew vs. Known – Which is Correct?

The key difference between knew and known lies in their tense and grammatical function as forms of the verb “to know.” Knew is the simple past tense, used for actions completed in the past. Known is the past participle, which typically requires an auxiliary verb (like “have,” “has,” “had,” “is,” “was,” “were”) and can also function as an adjective.

Knew or Known – Which is Correct?

Both “knew” and “known” are grammatically correct forms of the verb “to know,” but they are used in different contexts and tenses. The distinction is crucial for proper sentence construction.

• Knew serves as the simple past tense. It describes an action that was completed in the past. For example, “I knew the answer yesterday.”
• Known is the past participle. It is used in perfect tenses (e.g., present perfect, past perfect) with auxiliary verbs like “have,” “has,” or “had,” or in the passive voice with “is,” “was,” “were.” It can also function as an adjective. For example, “I have known him for years” or “The secret is known.”

The Best Trick to Remember the Difference

The simplest trick to remember the difference is to think about auxiliary verbs. If you need a helping verb like “have,” “has,” “had,” “is,” “was,” or “were” before the word, then known is almost always the correct choice. If the verb stands alone to describe a past action, then knew is likely what you need.

• Knew: Stands alone (e.g., “She knew it.”)
• Known: Needs a helper (e.g., “She has known it,” “It was known.”)

Word	Part of Speech	Meaning	Example
Knew	Verb (Simple Past Tense)	Had information or understanding in the past.	“I knew the answer to that question yesterday.”
Known	Verb (Past Participle), Adjective	(As participle) Used with auxiliary verbs for perfect tenses or passive voice; (As adjective) recognized, familiar.	“She has known him for many years.” (participle) “He is a well-known author.” (adjective)

How to Use Knew

Knew is the simple past tense form of the verb “to know.” It is used to describe an action or state of knowing that was completed at a specific point in the past. It does not require an auxiliary verb to form its tense.

Example 1: “I knew about the surprise party last week, but I kept it a secret.”

Example 2: “She knew the city well before she moved there.”

Example 3: “The detective knew the suspect’s alibi was false.”

What are the different forms of Knew?

“Knew” is already a specific past tense form of the irregular verb “to know.” The principal parts of the verb “to know” are:

• Base Form: know
• Simple Past: knew
• Past Participle: known

It does not have further forms like comparative or superlative degrees, as it is a verb, not an adjective. Its form remains “knew” regardless of the subject (e.g., I knew, you knew, he/she/it knew, we knew, they knew).

Etymology of the word Knew

The word “knew” derives from the Old English verb cnawan, meaning “to know, perceive, recognize, understand.” Its Germanic roots are evident across related languages, reflecting a common linguistic origin for the concept of knowledge. The irregular past tense “knew” evolved from earlier forms like cnēow in Old English, following a typical pattern of strong verbs.

How to Use Known

Known is the past participle form of the verb “to know.” It has several uses:

• With auxiliary verbs: Used in perfect tenses (present perfect, past perfect, future perfect) with “have,” “has,” or “had.”
• In the passive voice: Used with forms of “to be” (is, am, are, was, were, will be, etc.) to indicate that the subject receives the action.
• As an adjective: Describing something that is recognized, familiar, or publicly understood.

Example 1 (Present Perfect): “I have known him since we were children.”

Example 2 (Passive Voice): “The truth was not known until many years later.”

Example 3 (As an Adjective): “She is a well-known expert in her field.”

What are the different forms of Known?

“Known” is the past participle of the irregular verb “to know.” As a participle, it does not change form for person or number. When used as an adjective, it doesn’t typically take comparative or superlative forms (you wouldn’t say “more known”). However, it can be modified by adverbs (e.g., “well-known,” “widely known”).

• Base Form: know
• Simple Past: knew
• Past Participle: known

Etymology of the word Known

The word “known” also traces its origins back to the Old English cnawan. The past participle form cnāwen evolved into “known” over centuries, following the typical development of strong verb participles in English. Its core meaning of having information or being recognized has remained consistent throughout its linguistic history.

Related Concepts

Understanding these broader grammatical concepts can help clarify the correct usage of “knew” and “known” and other similar verb forms.

• Irregular Verbs: Many English verbs do not follow the standard pattern of adding “-ed” to form their past tense and past participle. “To know” is an irregular verb, with “know,” “knew,” and “known” as its principal parts. Mastering these irregular forms is essential for accurate writing.
• Verb Tenses: English verbs change form to indicate when an action occurs. “Knew” is specifically the simple past tense, indicating a completed action. “Known” is a past participle used in perfect tenses (which combine a helping verb with the participle to show a relationship between past and present actions) and the passive voice.

Examples from Media and Literature

• “He knew he had been wrong to doubt her.” – (Illustrates simple past tense)
• “If I had only known, I would have acted sooner.” – (Illustrates past perfect tense with “had known”)
• “It was a truth universally known that a single man in possession of a good fortune, must be in want of a wife.” – Jane Austen, Pride and Prejudice (Illustrates “known” in passive voice and as an adjective)
• “Everyone knew the old house was haunted.” – (Illustrates simple past tense)
• “His face was instantly known to millions around the world.” – (Illustrates “known” as an adjective)

Practice Exercises

Choose the correct word to complete the sentence.

1. She ______ the answer to the riddle immediately.
2. I have ______ him for over twenty years.
3. The secret was ______ by very few people.
4. They ______ that the road would be closed last Tuesday.
5. Has he ______ about the changes to the schedule?

Answer Key

1. knew
2. known
3. known
4. knew
5. known

Knew Synonyms

Since “knew” is the past tense of “to know,” its synonyms reflect past understanding or awareness. These are synonyms for the concept of “knowing” in the past.

Synonym	Definition
Understood	Grasped the meaning or nature of something in the past.
Realized	Became fully aware of something in the past.
Apprehended	Understood or perceived (often formally or intellectually).
Recognized	Identified someone or something from previous encounters or knowledge.

Known Synonyms

When “known” is used as an adjective, its synonyms relate to familiarity or recognition. As a participle, it implies having knowledge or being familiar.

Synonym	Definition
Familiar	Well-acquainted with or recognized.
Recognized	Identified from past knowledge or experience.
Acknowledged	Accepted or admitted to be true or to exist.
Publicized	Made widely known or promoted.
Apparent	Clearly visible or understood; obvious.

Frequently Asked Questions

Question 1: Can “known” ever be used without a helping verb?
No, not as a verb. “Known” is a past participle and must be used with an auxiliary verb (e.g., “have,” “has,” “had,” “is,” “was,” “were”) to form a complete verb phrase. However, it can function independently as an adjective (e.g., “a known fact,” “a well-known author”).

Question 2: Is “I had knew” ever correct?
No, “I had knew” is always incorrect. The past perfect tense requires the auxiliary verb “had” followed by the past participle. Therefore, the correct form is “I had known.”

Question 3: How do “knew” and “known” relate to “know”?
“Know” is the base form of the verb. “Knew” is its simple past tense, used for completed actions in the past. “Known” is its past participle, used in perfect tenses (with “have/has/had”) and the passive voice (with “to be”), and can also act as an adjective.

Conclusion

Distinguishing between “knew” and “known” is fundamental for clear and grammatically correct English. Remember that “knew” is the standalone simple past tense, indicating a past action of knowing. “Known” is the past participle, always requiring an auxiliary verb when used as part of a verb phrase, or functioning as an adjective. A solid grasp of these irregular verb forms enhances both your written and spoken communication, reflecting a strong command of the language.