chắc là

Probably

Level 3

Chắc là (often shortened to chắc) means 'probably' or 'most likely'. It shows you are fairly confident in a guess (around 70–90% certainty) but leaves room for doubt.

How It Works

Chắc là (often shortened to just chắc in casual speech) is an essential tool for expressing a confident guess or high probability. It translates to probably, most likely, or I bet.

Literally, the adjective chắc means firm, solid, or secure (e.g., cầm chắc = hold firmly). This physical sense of solidity evolved into expressing a 'firm' or confident guess. It indicates that you are fairly confident in your assumption, but you are not absolutely guaranteeing it. Because it leaves a small margin of doubt, native speakers frequently use it to soften statements, avoid sounding too aggressive, or save face if they turn out to be wrong.

Placement:
It is syntactically flexible but generally appears before the information it modifies:

  • Beginning of the clause: Chắc là + Subject + Predicate
  • Before the verb: Subject + chắc là + Predicate

Negation and Questions:

  • To say 'probably not', you do not negate chắc. Instead, you negate the verb, often pairing it with the denial particle đâu at the end: Chắc anh ấy không đến đâu (He probably won't come).
  • Không chắc and chưa chắc do not mean 'probably not'. They mean 'not sure' and 'not necessarily', respectively.
  • Chắc không? means 'Are you sure?', not 'Probably?'.

Nuance and Comparisons:

  • Unlike có lẽ (perhaps), which implies a 50/50 coin toss, chắc là shows strong confidence.
  • Unlike hình như (it seems), which relies on immediate sensory clues (like seeing dark clouds), chắc là is often based on internal logic or deduction.
  • Do not confuse it with chắc chắn (definitely). If you are 100% sure, you must use chắc chắn.
  • Important Caveat: While chắc là goes before the verb to mean 'probably', placing just chắc at the absolute end of a statement can mean 'for sure' or 'certainly' (e.g., Đội mình thắng chắc = Our team will win for sure). However, depending on the context and tone, it can also act as a skeptical or sarcastic rhetorical question (e.g., Anh đùa chắc? = Are you joking?).

Examples (4)

  1. Chắc là hôm nay trời sẽ mưa.

    It's probably going to rain today.

    Word by Word: Probably today sky will rain.

    Placed at the beginning of the clause to make a confident guess about the weather.

  2. Cô ấy chắc là đang ở nhà vì đã muộn rồi.

    She's probably at home now since it's so late.

    Word by Word: She probably is at home because already late.

    Placed directly before the verb phrase. The guess is based on logical deduction (it is late).

  3. Chắc anh ấy quên.

    He probably forgot.

    Word by Word: Probably he forgot.

    In casual speech, 'chắc là' is frequently shortened to just 'chắc'.

  4. Chắc là món này rất cay.

    This dish is probably very spicy.

    Word by Word: Probably dish this very spicy.

    Making an educated guess about the food before eating it.

Common Mistakes

  • Using 'chắc là' to mean 'I am 100% sure'.

    Tôi chắc là anh ấy sẽ đến 100%.
    Tôi chắc chắn anh ấy sẽ đến 100%.

    Because the standalone adjective 'chắc' means 'firm' or 'solid', learners mistakenly assume 'chắc là' means 'I am certain'. However, 'chắc là' means 'probably' and always contains a margin of doubt. For absolute certainty, use 'chắc chắn'.

  • Placing 'chắc là' at the end of the sentence to mean 'probably'.

    Anh ấy quên, chắc là.
    Chắc là anh ấy quên.

    English speakers often place 'probably' or 'I guess' at the absolute end of a sentence as an afterthought. In Vietnamese, 'chắc là' must precede the clause or the verb phrase it modifies to mean 'probably'. If you place 'chắc' at the very end of a statement, it does not mean 'probably'—depending on context, it either means 'for sure' (e.g., 'Tôi biết chắc' = 'I know for sure') or acts as a sarcastic rhetorical question (e.g., 'Anh đùa chắc?' = 'Are you joking?').

  • Saying 'không chắc' to mean 'probably not'.

    Different MeaningAnh ấy không chắc đến.
    Chắc là anh ấy không đến đâu.

    'Anh ấy không chắc đến' is a correct sentence, but it means he is not sure about coming. Learners often translate 'probably not' by negating 'chắc'. However, 'không chắc' means 'not sure' and 'chưa chắc' means 'not necessarily'. To say 'probably not', use 'chắc là' and negate the verb itself, often adding the particle 'đâu' at the end for natural phrasing.

How It Connects

Tap a pattern to see what it builds on and what it leads to.

chắc làLevel 3Probably

Learn This First

To understand 'chắc là' (probably), learners first need to be comfortable with the basic copula 'là' and how it is used to introduce clauses or states of being. It also helps to understand how Vietnamese expresses subjective thoughts (like 'nghĩ là') since 'chắc là' follows a similar syntactic structure to express a confident guess.

Words in This Pattern

chắc