说不定: Perhaps or Possibly in Chinese
说不定
说不定 is a fixed expression meaning ‘perhaps’ or ‘possibly,’ literally that something cannot be said with certainty. It normally introduces the uncertain proposition and may occur before or after its subject. The internal 不定 cannot be replaced by 没定 or separated from 说 when this possibility meaning is intended.
Published July 23, 2026
Reviewed July 23, 2026
01 / PATTERN
See the Structure
MODEL
说不定 + Subject + Predicate
Read the structure
说不定 is a fixed expression meaning ‘perhaps’ or ‘possibly,’ literally that something cannot be said with certainty. It normally introduces the uncertain proposition and may occur before or after its subject. The internal 不定 cannot be replaced by 没定 or separated from 说 when this possibility meaning is intended. Keep the model 说不定 + Subject + Predicate visible while you compare each sentence.
说不定他今天不会来了。
Perhaps he will not come today.
Choose the right context
Offer a plausible but uncertain explanation. Predict one possible future outcome. Soften a guess before a complete proposition.
他还没到，说不定堵车了。
He has not arrived; perhaps he is stuck in traffic.
Respect the boundary
Do not use it for a certain conclusion. Do not replace 不 with 没 inside the fixed expression. Do not strand 说不定 after the proposition as a final particle.
说没定他今天不来了。
(Perhaps he is not coming today.)
Repair the pattern
The fixed expression uses 没 instead of 不: The possibility marker is the fixed expression 说不定; its 不 cannot be replaced by 没. The proposition splits the fixed expression: 说不定 is one fixed possibility marker; its three syllables cannot be separated by the proposition.
说不定他今天不来了。
Use the repaired structure without changing the intended meaning.
02 / MAP
Read the Sentence
Read from left to right and notice the job performed by each part. The labels describe this example; they are not a rule that every Chinese sentence must copy.
说不定他今天不会来了。
Perhaps he will not come today.
说不定
说不定
This part occupies the 说不定 position in the model pattern.
他
Subject
This part occupies the Subject position in the model pattern.
今天
Predicate
This part occupies the Predicate position in the model pattern.
不会
说不定
This part occupies the 说不定 position in the model pattern.
来
Subject
This part occupies the Subject position in the model pattern.
了
Predicate
This part occupies the Predicate position in the model pattern.
03 / EXAMPLES
Examples You Can Reuse
Keep the structure stable while changing the people, objects, times, or conditions. Pinyin is shown as reading support; use the Chinese sentence and translation to confirm the grammar relationship.
说不定他今天不会来了。
Perhaps he will not come today.
他还没到，说不定堵车了。
He has not arrived; perhaps he is stuck in traffic.
明天说不定会下雪。
It might snow tomorrow.
04 / LIMITS
When to Use It — and When Not To
Use it when
- Offer a plausible but uncertain explanation.
- Predict one possible future outcome.
- Soften a guess before a complete proposition.
Do not use it when
- Do not use it for a certain conclusion.
- Do not replace 不 with 没 inside the fixed expression.
- Do not strand 说不定 after the proposition as a final particle.
05 / REPAIR
Compare Right and Wrong
Compare the smallest meaningful change. Each explanation identifies a placement, scope, form, or clause relationship instead of treating the whole sentence as one undifferentiated mistake.
说没定他今天不来了。
说不定他今天不来了。
The fixed expression uses 没 instead of 不
The possibility marker is the fixed expression 说不定; its 不 cannot be replaced by 没.
说他今天不定会来。
说不定他今天会来。
The proposition splits the fixed expression
说不定 is one fixed possibility marker; its three syllables cannot be separated by the proposition.
说没定他今天不来了。
The possibility marker is the fixed expression 说不定; its 不 cannot be replaced by 没.
说他今天不定会来。
说不定 is one fixed possibility marker; its three syllables cannot be separated by the proposition.
06 / PRACTICE
Practice the Grammar Point
Complete three short tasks in order: judge the pattern, repair a common error, and build the sentence. Feedback is fixed and reviewed, so these activities do not use a checker allowance.
1. Judge the sentence
2. Choose the correction
3. Build the sentence
Build a complete sentence with 说不定.
07 / APPLY
Apply It in Your Sentence
Write one original sentence with 说不定. Your draft moves to the checker through this browser session, selects this grammar point as the first review focus, and waits for you to submit.
08 / QUESTIONS
说不定: Perhaps or Possibly Questions
Does 说不定 literally involve speaking?
Not in this use. It functions as a fixed probability expression meaning ‘perhaps.’
Can the subject come before 说不定?
Yes. Both 说不定他会来 and 他明天说不定会来 are possible.
09 / SOURCES
Sources and Review Notes
These references support different parts of the lesson. GF0025-2021 supports level placement only; professional grammar works support the explanation, limits, examples, and cross-checks. Their inclusion does not imply endorsement.
Chinese Proficiency Grading Standards for International Chinese Language Education (GF0025-2021)
Ministry of Education and State Language Commission · Ministry of Education of the PRC · 2021
Locator: GF0025-2021 Appendix A, Level 4 item 【四27】, 固定短语：说不定 (printed p. 208)
Supports placement in HSK 4; it does not independently establish the usage explanation.
Official sourceModern Mandarin Chinese Grammar: A Practical Guide, 3rd ed.
Ross, Ma, Chen, He and Yeh · Routledge · 2024
Locator: Chapter 18, §18.7; Chapter 32, §32.5, restricted resultative ending -不定
Defines 说不定 as a fixed expression meaning perhaps or possibly and notes its restricted negative form.
Official source10 / CONTINUE
Continue with a Connected Rule
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