大概 vs 左右: approximating quantity in Mandarin
大概 (dàgài) and 左右 (zuǒyòu) both express approximation, but they differ in syntax and nuance. 大概 is an adverb placed before a number or statement to mean 'approximately' or 'probably', while 左右 is a particle placed after a specific number to mean 'or so'. The choice depends on word order and whether you need a precise range or a looser estimate.
Both 大概 and 左右 are used to indicate inexactness, but they occupy different positions and have distinct grammatical roles. 大概 is an adverb that precedes the quantity or clause it modifies, often implying a rough guess or a probabilistic nuance. 左右 is a postposition that follows a number or measure word, giving a narrow range around that value. Choosing between them requires attention to word order and the degree of precision you wish to convey.
When to use each
Use 大概 before a number or quantity (e.g. time, money, people) to mean 'approximately'. It often appears before the verb and is suitable when you are making a rough estimate based on general knowledge. 大概 can also be used before a statement to mean 'probably' (e.g. 大概他今天不来).
大概 conveys a broader, less precise approximation than 左右. It often carries a sense of subjective guesswork rather than a tight numerical range.
Use 左右 after a specific number or quantity to indicate 'approximately, give or take'. It is attached directly to the number (e.g. 十个人左右, 三天左右). It implies that the actual value is close to that number, with a small margin of error. 左右 is very common with time, age, price, and distance.
左右 cannot be used alone; it must follow a numeral or measure phrase. Unlike 大概, it does not modify the whole clause and cannot express probability.
At a glance
| 大概 | 左右 | |
|---|---|---|
| Part of speech | adverb | postposition (particle) |
| Position in sentence | before the quantity / verb | after the quantity / noun |
| Precision level | broader, more approximate | tighter, within a small range |
| Can express probability? | yes (e.g. 大概他不会来) | no |
| Example with number | 大概十个人 | 十个人左右 |
Examples
- 大概大概有十个人来了。Dàgài yǒu shí gè rén lái le.About ten people came.大概 placed before the verb to indicate approximation of the quantity.
- 左右他三十岁左右。Tā sān shí suì zuǒyòu.He is around thirty years old.左右 follows the age number directly.
- 大概大概三个小时以后到。Dàgài sān gè xiǎoshí yǐhòu dào.I'll arrive in about three hours.大概 modifies the time phrase, giving a rough estimate.
- 左右三个小时左右以后到。Sān gè xiǎoshí zuǒyòu yǐhòu dào.I'll arrive in three hours or so.左右 attached to the time phrase after the number.
- 大概大概他忘了。Dàgài tā wàng le.He probably forgot.Epistemic use of 大概 (probability), not approximation.
- 大概她买了大概十本书。Tā mǎi le dàgài shí běn shū.She bought approximately ten books.大概 placed before the quantity, natural in spoken Chinese.
Common mistakes
- Using 左右 before the number (e.g. 左右十个人) — 左右 must follow the number.
- Using 大概 after the number (e.g. 十个人大概) — 大概 is an adverb and should come before the number or verb.
- Using 左右 for probability (e.g. 左右他不来) — 左右 cannot express probability; use 大概 or 可能.
- Using both 大概 and 左右 together redundantly (e.g. 大概十个人左右) — while accepted in casual speech, it is verbose; choose one for clarity.
FAQ
- When do I use 大概 vs 左右 for approximation?
- Use 大概 before the quantity (e.g. 大概十个人) for a looser estimate when you aren't sure of the exact number. Use 左右 after the quantity (e.g. 十个人左右) for a more precise range around that number. 左右 is more common with specific measurements, while 大概 is also used for probability.
- Can 大概 and 左右 be used in the same sentence?
- Yes, but it is redundant: 大概十个人左右 is understood as 'approximately ten or so' but is often considered wordy. In formal writing, using one is sufficient.
- Does 左右 always attach to a number?
- Yes, 左右 must follow a numeral or a measure word phrase. It cannot be attached to a verb or clause. For example, you cannot say *左右来了 (incorrect).
- Is 大概 only for quantities?
- No, 大概 can also be used as a sentence adverb meaning 'probably' (e.g. 大概他今天不来). This meaning is separate from approximation and is quite common.