How It Works

The verb biết is used in several primary sentence structures:

Knowing facts or information: Subject + biết + Noun/Pronoun/Clause
Use this when you are aware of a situation, have a piece of information, or know of someone's identity. When connecting to a clause, the words là or rằng (that) are frequently used to bridge the verb and the clause (e.g., Tôi biết là...).
Indirect questions: Subject + biết + Question Word
You can use biết with question words like ai (who), gì (what), đâu (where), or khi nào (when) to form indirect questions (e.g., Tôi không biết anh ấy đi đâu - I don't know where he went).
Knowing a learned skill: Subject + biết + Verb / Noun
Use this for acquired abilities like speaking a language, swimming, or playing an instrument. When using a noun, it must imply an ability (e.g., Tôi biết tiếng Việt, Tôi biết võ). You can also use the highly common variation biết cách + Verb (know how to / know the method, e.g., Tôi biết cách nấu ăn).
Knowing a physical state: Subject + biết + Adjective
Biết is commonly paired with adjectives describing physical states like đói (hungry), mệt (tired), or đau (pain) to mean "to know the sensation of" or "to be capable of feeling" that state, rather than feeling it right at this exact moment (e.g., Tôi biết mệt - I get tired too).

Common Phrases:

Cho biết: To let someone know (e.g., Hãy cho tôi biết - Please let me know).
biết đâu / Ai biết: Who knows / maybe.
Biết bao / Biết mấy: So much / how much (used for emphasis).

Negative Form:
To say you do not know a fact or do not know how to do a skill, simply place không before the verb: không biết. However, it is highly common and often more polite to use chưa (not yet) instead: chưa biết (don't know yet), which softens the statement.

Question Form:
To ask "Do you know?", use the standard yes/no question frame có ... không?: Subject + có biết + [Noun/Verb/Clause] + không? (e.g., Bạn có biết bơi không?).

Important Distinctions:

Biết vs. Quen: Biết means knowing a fact or knowing who someone is superficially. Quen means being personally acquainted with someone.
Biết vs. Hiểu: Biết means possessing information. Hiểu means comprehending a concept or understanding speech.
Biết vs. Có thể / Được: Biết is for learned skills. có thể (placed before the verb) and được (placed after the verb) are used for physical capability, permission, or circumstantial possibility (e.g., Tôi bơi được).

Examples (5)

Tôi biết bơi.
I know how to swim.
Word by Word: I know swim.
Used directly with a verb to indicate a learned skill.
Anh ấy không biết chuyện đó.
He doesn't know about that matter.
Word by Word: He not know matter that.
Used with a noun phrase to indicate lacking factual information.
Tôi không biết anh ấy là ai.
I don't know who he is.
Word by Word: I not know he is who.
Used with a question word to form an indirect question.
Bạn có biết nhà hàng này ở đâu không?
Do you know where this restaurant is?
Word by Word: Friend have know restaurant this at where no?
A common way to ask for information using the có ... không? question frame and a question word.
Làm việc cả ngày, tôi cũng biết mệt.
Working all day, I get tired too.
Word by Word: Do work all day, I also know tired.
Used with an adjective describing a physical state to mean 'to know the sensation of' or 'to be capable of feeling'.

Common Mistakes

Using 'có thể' (can) instead of 'biết' for learned skills.
Tôi có thể nói tiếng Việt.
Tôi biết nói tiếng Việt.
English uses 'can' for both physical ability and learned skills. In Vietnamese, you must use biết for learned skills (like languages or swimming), while có thể is reserved for physical capability or circumstantial possibility.
Overusing 'cách' (how to) for basic skills.
Tôi biết cách bơi.
Tôi biết bơi.
Because English uses the phrase 'know how to', learners often insert 'cách' (method/way). While grammatically acceptable, it sounds unnatural for basic skills. Native speakers simply attach the verb directly to 'biết'.
Using 'không biết' when you don't understand what someone is saying.
(When someone speaks too fast) Tôi không biết.
Tôi không hiểu.
Use 'không hiểu' (I don't understand) for language comprehension. 'Không biết' means you don't possess the factual answer to a question.

How It Connects

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biếtLevel 1To Know / Know How to

Learn This First

To use 'biết' effectively, a learner needs to be comfortable with the lack of verb conjugation in Vietnamese, the standard SVO word order, and the system of kinship pronouns used for 'I' and 'you'.

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biết