不 vs 没 — How Mandarin Negation Actually Works
When to use 不 (bù) vs 没 (méi) for negation in Mandarin Chinese. The simple rule, the exceptions, and the patterns learners get wrong.
The short rule
Mandarin uses two different words for "not":
- bù不 negates pretty much everything except past actions — present states, habits, willingness, future intentions, equating sentences with 是.
- méi没 negates past actions and 有 (yǒu, "have") — and that's basically all it does.
If you remember just one thing: past actions and 有 take 没. Everything else takes 不.
不 — the default negator
Use 不 to negate verbs, adjectives, and modal verbs in the present, future, or habitual sense.
| wǒ我bù不qù去 | I'm not going / I don't go |
| tā他bù不shì是xué学shēng生 | He's not a student |
| wǒ我bù不xiǎng想chī吃 | I don't want to eat |
| tā他bù不gāo高 | He's not tall |
| wǒ我bù不néng能qù去 | I can't go |
Tone change: 不 before another 4th tone
不 is normally 4th tone (bù), but before another 4th-tone syllable it shifts to 2nd tone: 不是 is spoken bú shì, not bù shì. See the tones page for the full rule.
没 — for past actions and 有
没 (often written 没有 in full) negates completed actions and the verb 有.
| wǒ我méi没qù去 | I didn't go |
| tā他méi没lái来 | He didn't come |
| wǒ我méi没yǒu有qián钱 | I don't have money |
| wǒ我méi没yǒu有shí时jiān间 | I don't have time |
| wǒ我méi没chī吃guò过 | I haven't (ever) eaten it |
Never 不有
"Don't have" is 没有, not 不有. 不有 is grammatically wrong — full stop. 有 is one of the very few verbs that always rejects 不.
Side-by-side comparison
The same sentence with 不 vs 没 means two different things:
| wǒ我bù不chī吃 | I don't eat (it) / I won't eat (it) |
| wǒ我méi没chī吃 | I didn't eat (it) |
| tā他bù不lái来 | He's not coming / he won't come |
| tā他méi没lái来 | He didn't come |
| wǒ我bù不xiǎng想 | I don't want to / I'm not thinking about it |
| wǒ我méi没xiǎng想 | I didn't think about it |
Common mistakes
The classic learner trip-ups — wrong on top, right below:
Today is not January 1. (是 is always negated with 不.)
My younger sister is not 10 years old. (Again — 不是, not 没是.)
I don't have money. (有 always pairs with 没, never 不.)
I wasn't happy yesterday. (高兴 is a state, not a completed action — use 不 even in the past.)
He didn't come yesterday. (Completed past action — 没.)
The traps
Negative adjectives still take 不, even about the past
不 negates states, even in the past. 昨天他不高兴 (zuótiān tā bù gāoxìng — "he wasn't happy yesterday") uses 不, not 没, because being happy/unhappy is a state, not a completed action.
没 with 是 — not natural
The negation of 是 (to be) is always 不是, never 没是. Use 不是 in any time frame: "I wasn't a student then" is wǒ nàshí bú shì xuéshēng (我那时不是学生).
Habitual past = 不, not 没
"I didn't smoke (back then, as a habit)" is wǒ yǐqián bù chōuyān (我以前不抽烟). 不 here, because we're talking about a habit / general state, not a specific completed action. 没 would mean "I didn't smoke (this one cigarette/time)".
Related
Get the negation right the first time
不 vs 没 isn't hard once you've used it 50 times in real sentences. Kango drills it in scenarios where it actually matters — restaurant ordering, talking about your weekend, declining politely.
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