能 vs 可以 (néng vs kěyǐ): ability vs permission
能 (néng) expresses ability, capacity, or possibility, while 可以 (kěyǐ) primarily indicates permission or that something is allowed. Both can overlap when talking about possibility, but in requests and responses about permission, 可以 is the standard choice. Understanding this distinction helps you avoid using 能 where permission is meant and vice versa.
能 (néng) and 可以 (kěyǐ) both translate as 'can' or 'may' in English, but their core uses differ. 能 focuses on ability or possibility — whether someone has the capacity or something is possible. 可以 focuses on permission or option — whether someone is allowed to do something or whether a situation permits it. While 能 can sometimes be used for permission informally (especially in questions), 可以 is the more appropriate and polite choice for permission. In negative sentences, both can express prohibition, but the nuance and formality vary slightly.
When to use each
Use 能 to express ability or capacity, whether physical, mental, or situational (e.g., 我能举起来 'I can lift it'). Also used for possibility in impersonal contexts (e.g., 明天能下雨 'It can rain tomorrow'). In informal spoken Chinese, 能 can be used to ask for or give permission, though 可以 is more standard.
The negative form 不能 can mean both 'cannot' (lack of ability) and 'not allowed' (prohibition), depending on context. For a learned skill like speaking Chinese, use 会 instead.
Use 可以 to ask for permission (e.g., 可以进来吗？ 'May I come in?') or to grant it (可以 'Yes, you may'). Also used to express possibility in a neutral, permissive sense (e.g., 这个办法可以试一试 'This method can be tried'). In some contexts, 可以 indicates sufficiency or adequacy (e.g., 这个可以了 'This is enough').
For objective possibilities like weather events, 可以 is less natural than 能 (e.g., 明天可以下雨 sounds odd). 可以 is not used for personal ability (e.g., 'I can swim' is 能游泳, not 可以游泳).
At a glance
| 能 | 可以 | |
|---|---|---|
| Primary meaning | Ability / capacity | Permission / option |
| Ability | Common (physical/mental capacity) | Not used (use 能) |
| Permission (standard) | Informal (used in speech) | Standard and polite |
| Objective possibility (e.g., weather) | Common (能下雨) | Unnatural (可以下雨 sounds odd) |
| Negation (prohibition) | 不能 – very common; can mean 'cannot' or 'not allowed' | 不可以 – more formal; mainly means 'not allowed' |
| Sufficiency / adequacy | Not used | 可以 (这个可以了 'This is enough') |
Examples
- 能他能跑得很快。Tā néng pǎo de hěn kuài.He can run very fast.Expresses physical ability — use 能, not 可以.
- 可以我可以坐这里吗？Wǒ kěyǐ zuò zhèlǐ ma?May I sit here?Asking permission — 可以 is the standard and polite choice.
- 可以——我可以进来吗？——可以。——Wǒ kěyǐ jìnlái ma?——Kěyǐ.—May I come in?—Yes, you may.Using 可以 alone to grant permission is very natural.
- 能明天能下雨。Míngtiān néng xià yǔ.It can rain tomorrow.Objective possibility — 能 is the correct choice; 可以 would sound unnatural.
- 能你不能迟到。Nǐ bù néng chídào.You cannot be late.Prohibition expressed with 不能 is very common in spoken Chinese. 不可以 is also correct but more formal.
- 可以这个办法可以试试。Zhège bànfǎ kěyǐ shìshi.This method can be tried / It's OK to try this method.Expresses possibility with a permissive nuance — 可以 works here.
Common mistakes
- Using 可以 for personal ability: e.g., *我可以游泳 to mean 'I can swim' — use 能 (or 会 for learned skills).
- Using 能 for permission in formal contexts: e.g., *能进来吗？ is understood but 可以进来吗？ is more appropriate.
- Using 可以 for objective possibility like weather: e.g., *明天可以下雨 is unnatural; use 能.
- Using 不可以 to mean 'cannot' when lacking ability: e.g., *我不可以举起这个 means 'I am not allowed to lift this', not 'I cannot lift it' — use 不能.
- Confusing 会 and 能 for ability: e.g., using 能 for a learned skill when 会 is required (他会说中文, not 他说中文).
FAQ
- When do I use 能 vs 可以 for ability?
- Use 能 for ability (physical/mental capacity, e.g., 他能游泳 'He can swim'). Use 可以 for permission (e.g., 我可以游泳 'I am allowed to swim'). For learned skills, use 会 instead of 能 or 可以 (e.g., 我会说中文 'I can speak Chinese').
- Can 能 be used for permission?
- Yes, informally, 能 can be used to ask for or give permission, especially in spoken Chinese (e.g., 能进来吗？). However, 可以 is more standard and polite, especially in formal situations. In responses, 可以 is the typical affirmative answer.
- How do I say 'cannot' for prohibition?
- Both 不能 and 不可以 mean 'not allowed'. 不能 is extremely common in everyday speech (e.g., 你不能在这里吸烟 'You cannot smoke here'). 不可以 is also correct but sounds more formal or emphatic. Use 不能 if you want to sound natural in most contexts.
- Why is 明天可以下雨 unnatural?
- For impersonal possibilities like weather events, 能 is preferred because it conveys objective possibility. 可以 involves a sense of permission or option, which doesn't fit impersonal natural phenomena. So 明天能下雨 is correct, while 明天可以下雨 sounds like the rain is being given permission, which is odd.