How to say 'can I' naturally in Chinese

WHEN IT FITS

Asking permission to do somethingChecking if something is acceptableBoth formal and casual

The permission-ability split is one of the structural differences between Chinese and English that a translator will never teach you:

可以 = permission. 我可以进来吗？(May I come in?). The question is about whether it is allowed or acceptable.
能 = ability / possibility. 你能帮我吗？(Can you help me? / Are you able to help?). The question is about capability or feasibility.
会 = learned skill. 我会游泳 (I can swim / I know how to swim). The statement is about acquired ability.

English blurs all three into “can.” Chinese keeps them distinct, and native speakers choose instinctively. Using 可以 where 能 belongs (or vice versa) is one of the most reliable markers of a translated sentence.

行吗 is the everyday shortcut among friends: it means “does that work?” and carries zero formality. 可以吗 is safe everywhere; 行吗 is warmer but requires a casual relationship.

HOW PEOPLE ACTUALLY SAY IT

我可以坐这里吗？

Wǒ kěyǐ zuò zhèlǐ ma?

Can I sit here?

Asking permission

明天晚一点到，可以吗？

Míngtiān wǎn yìdiǎn dào, kěyǐ ma?

I'll arrive a bit late tomorrow — is that okay?

Checking acceptability

CHOOSE BY SITUATION

能不能

néng bu néng

Can or can't / is it possible.

Asking about ability or feasibility, not just permission — 能不能帮我？= Can you help me?

行吗

xíng ma

Is that okay / does that work.

Very casual check-in among equals — warm but informal