Choosing Không versus Chưa

Both không and chưa can make an English translation negative, but they do not take the same view of the situation. Không simply rejects a predicate: something is not true, does not happen, or did not happen in the relevant frame. Chưa says that a situation has not been realized up to a reference point—often “not yet,” and sometimes “never so far” with life experience.

The practical question is not “Which word means not?” Ask whether the speaker presents an open timeline leading toward a possible or expected event. If no such boundary matters, use không. If the event or state remains pending at “now,” “then,” or another stated deadline, use chưa. The related choice between đã and rồi is treated on its own page.

Quick decision aid

Follow this decision tree:

1. Does the sentence mean simply “not,” “doesn’t,” or a settled “didn’t”? Start with không.
2. Can you naturally add “yet,” “so far,” or “by that time”? Start with chưa.
3. Are you asking about a habit or preference? Use a có ... không? question.
4. Are you checking progress toward an expected event? Use ... chưa?, optionally đã ... chưa?.

Không rejects the predicate

Không normally comes before the predicate it negates. It works with events, properties, locations, and possession.

In the first example, không describes a habit or preference; there is no pending cup of coffee. In the second, hôm qua closes the past frame, and không đi reports nonoccurrence. In the third, a property is denied. Replacing these with chưa would create a “not yet” perspective: perhaps the person has not drunk coffee yet today, Lan had not gone to work by some past time, or the kitchen has not become spacious yet.

For negative existence or possession, Vietnamese normally uses không có, because có is the predicate being negated:

This differs from locating an entity with ở. For that broader contrast, see absence with không có.

Chưa keeps a boundary open

Chưa also comes before the predicate in a statement, but it instructs the listener to compare the current situation with a possible later realization.

The reference point need not be the present. Đến mười giờ tối establishes a past deadline. Chưa nhận được says the result had not arrived by then. The marker is therefore aspectual and temporal in perspective, not a special present-tense form.

With an experience predicate, chưa từng means “have never so far”:

The time span is the person’s experience up to now. A later trip remains logically possible. Compare the stronger, context-dependent rejection Tôi không bao giờ đi tàu đêm “I never travel by night train,” which describes a habit or policy.

Minimal pair: the same morning, a different stance

At 8 a.m., both sentences could describe the same physical fact. Không closes or simply negates the breakfast event; it may imply that the speaker skipped it. Chưa keeps the event open and encourages an inference that eating later is relevant. At noon, không ăn sáng is normally the better report of having skipped breakfast; chưa ăn sáng can sound humorous or marked unless breakfast is genuinely still planned.

This is the genuine overlap zone. Contexts involving a bounded event before a deadline often allow either word, but the speaker’s stance changes. Vietnamese marks that stance directly where English may leave it to didn’t versus haven’t ... yet.

Contexts where the intended meaning selects one form

For a stable preference, only không expresses the intended meaning:

Tôi chưa ăn thịt means “I haven't eaten meat yet,” perhaps today or in one’s life. It does not state vegetarian practice.

For a progress update in which completion remains pending, chưa is the direct choice:

Máy không sửa xong does not give the intended “not yet” status. Depending on context, it may mean that someone does not finish repairing it or that the repair fails. Chưa ... xong identifies the unreached endpoint.

Questions and short answers

A neutral polar question often uses có ... không?. A status question uses final chưa?, often paired with preverbal đã.

Short answers preserve the type of question. Có / Không answers a neutral polarity question; Rồi / Chưa answers whether the expected stage has been reached. The full subject or predicate can be repeated when clarity or politeness requires it.

A dialogue where the choice changes the plan

The opening chưa? checks progress toward sending. Chưa ký leaves the signature pending. The question with không đến tests a factual assumption about attendance, while không có ở phòng reports absence during a completed morning interval. The speakers’ workplace roles support chị and ông ấy; switching to casual pronouns would change the social tone, not the negation choice.

Register and regional notes

Không and chưa are neutral in conversation and standard writing throughout Vietnam. Chẳng can replace không in expressive speech and literary prose, while chả is conversational and especially associated with Northern speech; neither normally replaces the “not yet” value of chưa. Hổng is (regional: Southern, informal) for negative không in some speech, but standard writing retains không. These variants should not be mixed into neutral prose without a register or character reason.

Formal reports may make the reference point explicit: Đến ngày 30 tháng 6, đơn vị chưa nhận được hồ sơ “As of June 30, the unit had not received the file” (formal). Everyday speech relies more readily on shared timing: Chưa nhận được “Haven’t received it yet.” The underlying choice is the same.

Common Mistakes

1. Using chưa for a stable habit

Chưa uống means that no drinking has occurred up to a reference time; không uống states the habit or choice.

2. Losing the pending meaning with không

The request for more time makes the unreached endpoint central, so chưa ... xong is the natural repair.

3. Copying English present-perfect marking word for word

Vietnamese places chưa directly before the predicate. Có ... chưa? can occur as a question frame in some contexts, but it is not assembled as an English auxiliary chain.

4. Answering every negative question with chưa

Answer Chưa only if “not yet” is the stance you want—for example, if learning to swim is anticipated.

Key Takeaways

• Không rejects a fact, habit, property, or event within its frame.
• Chưa says that a situation has not been realized by a reference point and remains conceptually open.
• In overlap contexts, không tends to close the event, while chưa presents it as pending.
• Use có ... không? for neutral polarity and (đã) ... chưa? to check progress or experience.
• English tense labels are clues, not rules; choose the Vietnamese discourse stance.