Have you ever wondered whether to write “I knew the answer” or “I have known the answer”? Both knew and known are correct English words, but they serve different grammatical purposes. The confusion usually occurs because both come from the verb know, yet they are used in different verb forms and tenses.
You may encounter these words in everyday conversations, emails, academic writing, books, and professional communication. Understanding the difference will help you choose the correct form when describing something you understood in the past or something you have known over a period of time.
Quick Answer
Knew is the simple past tense of the verb know, while known is its past participle. They are both correct, but they cannot be used interchangeably.
| Form | Correct? | Verb Form | Main Use |
| Knew | Yes | Simple past | Describes something someone understood or was aware of in the past. |
| Known | Yes | Past participle | Used with helping verbs such as have, has, and had, and in passive constructions. |
Examples:
- I knew the answer yesterday.
- I have known her for ten years.
- They had known about the problem before the meeting.
Remember: Use knew for the simple past and known when a past participle is required.
You can learn more about Jesus vs Jesus’s to understand the correct possessive spelling when referring to something belonging to Jesus.
Meaning and Definition
Meaning of Knew
Knew means understood, recognized, or had information about something in the past. It describes knowledge or awareness that existed at an earlier time.
It is commonly used when talking about past experiences, previous information, decisions, or things someone understood.
For example:
- I knew the answer before the teacher explained it.
- She knew that something was wrong.
- We knew each other when we were children.
In each sentence, knew describes a state of knowledge or awareness in the past.
Definition of Knew
Knew is the simple past tense of the irregular verb know. It means to have been aware of, familiar with, or informed about something at a particular time in the past.
It is used independently as the main verb in simple past sentences, usually with a subject.
For example:
- He knew the truth.
- They knew where to find us.
- I knew she would succeed.
Meaning of Known
Known means recognized, understood, or familiar to someone. It is the past participle of know and commonly appears with helping verbs to describe knowledge that existed before or continued up to a particular point.
For example:
- I have known him since childhood.
- She had known about the situation for months.
- He is known for his honesty.
The word can also describe someone or something that is recognized by other people.
Definition of Known
Known is the past participle of the irregular verb know. It refers to having information, awareness, familiarity, or recognition of someone or something.
It is commonly used with auxiliary verbs such as have, has, and had. It also appears in passive constructions with forms of be.
For example:
- She has known the answer for years.
- We had known about the changes.
- The author is known throughout the country.
Unlike knew, known generally needs a helping verb when it functions as part of a perfect verb construction.
Main Difference
The main difference between knew and known is their grammatical function. Both come from the verb know, but they are used in different verb forms.
| Feature | Knew | Known |
| Base verb | Know | Know |
| Part of speech | Verb | Verb |
| Verb form | Simple past | Past participle |
| Regular or irregular | Irregular verb form | Irregular verb form |
| Helping verb required | No, in simple past sentences | Yes, in perfect constructions |
| Common pattern | Subject + knew + object | Subject + have/has/had + known |
| Example | I knew the answer. | I have known the answer. |
Knew describes knowledge or awareness in the past.
Known is used with helping verbs to form perfect tenses or passive constructions.
Consider these examples:
- I knew Sarah in college. This means I was familiar with Sarah during that past period.
- I have known Sarah for ten years. This means I became familiar with Sarah ten years ago and still know her.
Another important difference is that known can appear in passive expressions:
- He is known as a talented musician.
- The area is known for its beautiful scenery.
You cannot replace known with knew in these constructions.
Which One Is Correct?
Both knew and known are correct English words. Neither is a misspelling. However, they have different grammatical functions, so you must choose the one that fits your sentence.
Use knew when describing something someone understood or was aware of in the past.
- I knew about the meeting yesterday.
- She knew the correct answer.
- They knew the risks before starting.
Use known when forming perfect tenses or passive constructions.
- I have known him for years.
- She had known the truth.
- The building is known for its architecture.
The following comparison makes the difference clear:
| Sentence | Correct or Incorrect | Explanation |
| I knew him when I was young. | Correct | Simple past tense |
| I have known him for years. | Correct | Present perfect tense |
| I have knew him for years. | Incorrect | Use the past participle known. |
| I had known the answer. | Correct | Past perfect tense |
| She is known for her work. | Correct | Passive construction |
| She is knew for her work. | Incorrect | Use known after is. |
Grammar and Usage
Understanding the verb forms of know makes it easier to use knew and known correctly.
Verb Forms of Know
The verb know is irregular, meaning it does not form its past tense by simply adding -ed.
Here are its main forms:
| Verb Form | Word | Example |
| Base form | Know | I know the answer. |
| Third-person singular | Knows | She knows the truth. |
| Simple past | Knew | He knew my name. |
| Past participle | Known | I have known him for years. |
| Present participle | Knowing | Knowing the rules helps. |
Knew in the Simple Past Tense
Use knew to describe knowledge, awareness, or familiarity that existed in the past.
Structure:
Subject + knew + object/complement
Examples:
- I knew the answer.
- She knew his address.
- They knew what to do.
You can also use knew in negative and interrogative sentences.
Examples:
- I did not know about the problem.
- Did you know her before?
- He didn’t know where to go.
Notice that after did or didn’t, you must use the base form know, not knew.
Known in Perfect Tenses
Use known with the appropriate form of have to create perfect tenses.
Present perfect:
Subject + have/has + known
- I have known him since 2015.
- She has known the answer for a long time.
Past perfect:
Subject + had + known
- They had known about the issue before the announcement.
- I had known her for several years before we became colleagues.
Modal perfect:
Modal + have + known
- You should have known the consequences.
- He might have known about the changes.
- I would have known if someone had told me.
Known in Passive Constructions
Known also appears in passive sentences, often with is, are, was, or were.
Examples:
- She is known for her kindness.
- These facts are known to researchers.
- He was known as a skilled writer.
- The location was previously known by another name.
Knew vs Known in Different Sentence Structures
| Sentence Pattern | Correct Example |
| Simple past | I knew the answer. |
| Present perfect | I have known the answer for years. |
| Past perfect | I had known the answer before the test. |
| Modal perfect | You should have known better. |
| Passive voice | The place is known for its history. |
| Past passive | The village was known by another name. |
An important point is that know is generally a stative verb. It describes a state of understanding or awareness rather than an ongoing physical action. Therefore, it is not normally used in continuous forms.
For example:
- Correct: I have known her for years.
- Incorrect in standard usage: I have been knowing her for years.
Discover why Chow Fun and Chow Mein have different textures to better understand how noodle thickness, ingredients, and cooking methods influence their taste and appearance.
How to Use Knew and Known
How to Use Knew
Use knew when talking about something you understood, recognized, or were aware of at a past time.
Common sentence patterns include:
1. Knew + noun
- I knew the answer.
- She knew the rules.
- He knew my father.
2. Knew + that-clause
- I knew that you were right.
- She knew that the situation was serious.
- They knew that the decision would be difficult.
3. Knew + question word
- I knew where he lived.
- She knew why they had left.
- We knew how the system worked.
4. Knew + someone or something
- I knew him from school.
- She knew the city very well.
- They knew each other before joining the company.
How to Use Known
Use known when a sentence requires a past participle.
1. Have/Has + Known
Use this structure when knowledge or familiarity began in the past and continues into the present, or when the past experience is relevant to the present.
- I have known him since childhood.
- She has known about the project for months.
- We have known each other for a long time.
2. Had + Known
Use this structure when describing knowledge that existed before another past event.
- I had known the truth before he told me.
- She had known him for years before they married.
- They had known about the problem before the inspection.
3. Be + Known
Use this structure to describe recognition, reputation, or identification.
- He is known for his excellent writing.
- The city is known for its historical buildings.
- She was known as a talented artist.
4. Should Have + Known
Use this structure when expressing that someone was expected to understand or recognize something.
- You should have known the rules.
- I should have known better.
- They should have known about the possible risks.
Examples
The following examples show how to use knew and known naturally in everyday English and formal communication.
Examples of Knew
- I knew you would understand my decision.
- She knew the answer to every question.
- We knew about the changes before the announcement.
- He knew that his friend needed help.
- They knew each other from university.
- I never knew how difficult the job would be.
- My parents knew about my plans.
- She immediately knew something was wrong.
- Nobody knew where the missing documents were.
- He knew the importance of hard work.
- I knew I had made the right choice.
- The teacher knew that the students were prepared.
- We knew the journey would take several hours.
- She knew how to solve the problem.
- I wish I knew the answer to that question.
Examples of Known
- I have known him since we were children.
- She has known about the situation for weeks.
- We have known each other for a long time.
- He had known the truth before the investigation began.
- The writer is known for his excellent novels.
- This city is known for its historical buildings.
- The problem has been known for several years.
- She is widely known as an experienced teacher.
- They have known about the risks since the beginning.
- The company is known for providing quality services.
- I should have known that he would arrive late.
- Nobody had known about the secret before yesterday.
- The area was once known by a different name.
- He might have known the answer already.
- The scientist is internationally known for her research.
Comparing Knew and Known in Sentences
These examples demonstrate how changing the verb form changes the grammatical structure.
| Knew | Known |
| I knew her in school. | I have known her since school. |
| He knew the answer. | He has known the answer for years. |
| We knew about the event. | We had known about the event. |
| She knew the truth. | She should have known the truth. |
| They knew the place. | The place is known for its beauty. |
Common Mistakes
Although knew and known are easy to understand individually, learners sometimes confuse their grammatical forms.
Here are some common mistakes and how to correct them.
1. Using Knew After Have
Incorrect: I have knew him for five years.
Correct: I have known him for five years.
Why it happens: Learners sometimes use the simple past form after have because they know that the sentence refers to the past.
However, present perfect tense requires a past participle, not a simple past form.
2. Using Known Without a Helping Verb
Incorrect: I known the answer yesterday.
Correct: I knew the answer yesterday.
Why it happens: Some learners confuse the past participle with the simple past form.
When describing a completed past situation in a simple past sentence, use knew.
3. Using Knew After Had
Incorrect: She had knew about the problem.
Correct: She had known about the problem.
Why it happens: The past perfect tense requires had followed by a past participle. Since known is the past participle of know, it is the correct choice.
4. Using Knew in Passive Constructions
Incorrect: He is knew for his honesty.
Correct: He is known for his honesty.
Why it happens: Learners may incorrectly assume that every past-related expression requires the simple past form.
However, passive constructions use the past participle.
5. Using Knew After Modal Perfect Expressions
Incorrect: You should have knew the answer.
Correct: You should have known the answer.
Why it happens: The structure should have requires a past participle. The same rule applies to could have, would have, and might have.
6. Using Knew After Did
Incorrect: Did you knew about the meeting?
Correct: Did you know about the meeting?
Why it happens: The auxiliary verb did already marks the past tense. Therefore, the main verb must remain in its base form, know.
7. Using Been Knowing Instead of Have Known
Incorrect: I have been knowing her since childhood.
Correct: I have known her since childhood.
Why it happens: Learners sometimes apply continuous tense patterns to stative verbs. In standard English, know generally does not take the continuous form when describing familiarity or awareness.
Linguistic Insight
The difference between knew and known becomes clearer when we examine the history and structure of the verb know.
Both Words Come From the Same Verb
Knew and known are forms of the same English verb, know. The verb is irregular, meaning its past forms do not follow the regular pattern of adding -ed.
Instead of using forms such as knowed or knowed, standard English uses:
- Know: Base form
- Knew: Simple past
- Known: Past participle
This irregular pattern is part of the historical development of English verbs.
Historical Origin of Know
The verb know comes from Old English cnāwan, which carried the meaning of recognizing, identifying, or understanding something.
It has Germanic roots and is historically related to words in other languages that express recognition or knowledge.
Over time, its spelling and pronunciation developed into the modern English forms we use today.
Morphological Difference
In linguistics, morphology refers to the way words change their forms to express grammatical information.
The words knew and known demonstrate an irregular verb pattern.
- Knew marks the simple past tense.
- Known marks the past participle.
These forms are not interchangeable because they perform different grammatical functions.
Pronunciation Difference
Knew and known also have different pronunciations.
| Word | Pronunciation (IPA) | Sounds Like |
| Knew | /nuː/ in American English | New |
| Known | /noʊn/ in American English | Nown |
In British English, the pronunciations are generally /njuː/ for knew and /nəʊn/ for known.
An interesting detail is that knew is a homophone of new. Both words sound identical in the same variety of English, although their meanings and spellings are different.
The pronunciation of known includes an additional final /n/ sound.
Why Learners Confuse Knew and Known
The confusion mainly occurs because both words express knowledge or awareness and refer to situations connected with the past.
However, English grammar distinguishes between a simple past verb and a past participle.
Understanding this distinction helps learners recognize why sentences such as “I knew him” and “I have known him” are both correct but follow different grammatical patterns.
Usage Tips
Use these practical tips to remember when to choose knew or known.
- Remember the verb sequence: Learn the three main forms together: know, knew, known.
- Look for have, has, or had: If these helping verbs introduce a perfect tense, use known.
- Use knew for simple past: When describing something you understood or were aware of in the past, choose knew.
- Check for passive voice: Expressions such as is known, was known, and are known require known.
- Remember modal perfect structures: Use known after expressions such as should have, could have, and might have.
- Watch out for did: Use know, not knew, after did or didn’t.
- Practice complete sentences: Learning the words in context makes their grammatical differences easier to remember.
A useful memory trick is:
- Knew = Past
- Known = Past participle
Remembering this simple distinction will help you avoid most mistakes.
Expert Suggestion
As a grammar teacher, I recommend learning knew and known as part of the complete irregular verb sequence rather than memorizing them separately.
Whenever you write a sentence, first identify its tense and structure.
Ask yourself:
- Am I describing something that happened or was true in the past? Use knew.
- Am I using have, has, or had to form a perfect tense? Use known.
- Am I describing how someone or something is recognized? Use known in the appropriate passive construction.
For ESL learners, students, and professional writers, practicing these three patterns is especially useful:
- I knew the answer.
- I have known the answer.
- The answer is known.
Once you understand these patterns, choosing between the two words becomes much easier.
Summary
Knew and known are both correct forms of the irregular English verb know, but they have different grammatical functions.
- Knew is the simple past tense of know. Use it to describe knowledge, awareness, or familiarity in the past.
- Known is the past participle of know. Use it with have, has, or had in perfect tenses and in passive constructions.
- Both forms are standard in American and British English.
- Do not use knew after have, has, or had.
- Do not use known as a simple past verb without an appropriate grammatical structure.
The easiest way to remember the difference is that knew describes past knowledge, while known is the past participle used in perfect tenses and passive constructions.
Frequently Asked Questions
1. What is the main difference between knew and known?
Knew is the simple past tense of know, whereas known is its past participle. Use knew for simple past sentences and known with helping verbs or in passive constructions.
2. Is knew or known correct?
Both are correct English words. However, their grammatical uses are different. For example, “I knew him” and “I have known him” are both correct.
3. Is knew the past tense of know?
Yes. Knew is the simple past tense of know. For example, “I knew the answer before the teacher explained it.”
4. Is known the past tense of know?
No. Known is the past participle of know, not its simple past tense. The simple past form is knew.
5. Should I use knew or known after have?
Use known after have. For example, “I have known her for many years” is correct, while “I have knew her” is incorrect.
6. Should I use knew or known after had?
Use known after had when forming the past perfect tense.
Correct: She had known about the problem before the meeting.
Incorrect: She had knew about the problem before the meeting.
7. Is it I knew you or I have known you?
Both expressions are correct, but they communicate different time relationships.
- “I knew you” describes familiarity in the past.
- “I have known you” describes familiarity that began in the past and continues into the present.
8. Is it should have knew or should have known?
Should have known is correct. Modal perfect constructions require a past participle after have, and known is the past participle of know.
9. Is it well known or well knew?
Well known is correct when describing someone or something that is widely recognized or familiar.
Example: She is a well-known author.
Well knew is not the standard expression for describing someone’s reputation.
10. Can I use known without have or has?
Yes. Known can appear without have or has in passive constructions and adjective-like expressions.
Examples:
- He is known for his kindness.
- The facts are well known.
- She was known as a talented artist.
11. What is the negative form of knew?
The negative simple past form is did not know or didn’t know.
Example: I didn’t know about the meeting.
Do not write “I didn’t knew” because did already indicates the past tense.
12. What is the difference between knew and new?
Knew is the simple past tense of know, while new is an adjective describing something recently created, acquired, or introduced.
Examples:
- I knew the answer.
- She bought a new phone.
Both words have the same pronunciation in English, but their meanings and spellings are different.
13. Is known used in American and British English?
Yes. Known is the standard past participle of know in both American and British English. There is no difference in its grammatical function between these varieties.
14. Why is know, knew, known an irregular verb?
It is irregular because its past tense and past participle do not follow the usual pattern of adding -ed to the base verb. Instead, English uses the established forms knew and known.
15. Can I say I have been knowing someone?
In standard English, this construction is generally incorrect when describing familiarity with someone. Use I have known someone instead because know is normally a stative verb and is not commonly used in continuous forms.
