The short version: -(으)ㄹ 수 있어요 means can: 갈 수 있어요 (I can go), 먹을 수 있어요 (I can eat it). For can't, the everyday form is 못 + verb: 못 가요. -(으)ㄹ 줄 알아요 means know how to: 운전할 줄 알아요. And Can I…? asking permission is a different pattern altogether: 여기 앉아도 돼요?
English “can” covers several different ideas: being able to do something, knowing how to do it, being allowed to do it, and asking someone to do it for you. Korean gives most of these their own form. Learning which is which is what stops a learner from asking a stranger whether they are physically capable of sitting down.
Three questions, three patterns
-(으)ㄹ 수 있어요: can
The pattern literally means “there is a way to”: 수 is a way or means, and 있어요 says it exists. How it attaches depends on the last sound of the verb stem.
| Stem ends in | Add | Example | Romanisation |
|---|---|---|---|
| a vowel | -ㄹ 수 있어요 | 가다 → 갈 수 있어요 | gal su isseoyo |
| ㄹ | nothing extra | 만들다 → 만들 수 있어요 | mandeul su isseoyo |
| a consonant | -을 수 있어요 | 먹다 → 먹을 수 있어요 | meogeul su isseoyo |
| ㄷ (irregular) | ㄷ → ㄹ | 듣다 → 들을 수 있어요 | deureul su isseoyo |
| ㅂ (irregular) | ㅂ → 우 | 돕다 → 도울 수 있어요 | doul su isseoyo |
Can't: 못, -(으)ㄹ 수 없어요, -지 못해요
Korean has three ways to say cannot. They mean the same thing and differ mainly in register.
Everyday speech
못 가요mot gayoI can't go.
Put 못 directly before the verb. By far the most common.
Neutral
갈 수 없어요gal su eopseoyoI can't go. / It's not possible.
The negative of 수 있어요.
Formal or written
가지 못해요gaji motaeyoI am unable to go.
Common in news, notices and formal speech.
With 하다 verbs
수영 못 해요suyeong mot haeyoI can't swim.
못 goes right before 하다, not before the noun.
못 or 안: can't, or won't?
Both make a sentence negative, but they answer different questions. 못 says something prevents you. 안 says you simply are not doing it.
-(으)ㄹ 줄 알아요: know how to
For a skill you have learned, such as driving, cooking, swimming or speaking a language, Korean often uses -(으)ㄹ 줄 알다 (know how to) and -(으)ㄹ 줄 모르다 (not know how to).
The difference from 수 있어요 shows up when the skill and the situation disagree:
못해요 or 못 해요: bad at, or can't?
Written as one word, 못하다 means to be bad at something, and its opposite is 잘하다 (to be good at). With a space, 못 하다 means cannot do. They are pronounced the same, so in speech context decides.
One word: bad at
노래를 못해요.noraereul motaeyoI'm bad at singing.
Two words: can't do
오늘은 숙제를 못 해요.oneureun sukjereul mot haeyoI can't do my homework today.
This is also the standard modest answer to a compliment. When someone says 한국어 잘하시네요! (Your Korean is good!), the usual reply is 아니에요, 아직 잘 못해요 (No, I'm not good at it yet).
“Can I…?” and “Can you…?”
English uses “can” for permission and for requests. Korean uses other patterns, and this is where the 수 있어요 habit causes odd-sounding questions.
Asking permission: Can I…?
Literally “Is it all right even if I…?”
Polite request: Could you…?
Here 수 있어요 is correct, because you are asking whether the other person is able to do you a favour.
Check yourself
Ability, know-how, choice or permission?
Something prevents you: 못.
With noun + 하다, 못 goes right before 하다.
읽다 ends in a consonant, so -을 수 있어요.
Permission: -아/어도 돼요?
Know how to: -(으)ㄹ 줄 알다.
ㄷ-irregular: ㄷ becomes ㄹ before a vowel, 들을 수 있어요.
Say what you can do, and what you can't
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Learn Korean with Hanguljo - FreeQuick reference
- Can
- Vowel or ㄹ stem + ㄹ 수 있어요 (갈 수, 만들 수); consonant stem + 을 수 있어요 (먹을 수). 듣다 → 들을, 돕다 → 도울.
- Can't
- 못 + verb (못 가요), -(으)ㄹ 수 없어요, formal -지 못해요. 하다 verbs: 수영 못 해요.
- 못 vs 안
- Can't (circumstances) vs don't / won't (choice).
- Know how
- -(으)ㄹ 줄 알아요 / 몰라요: 운전할 줄 알아요.
- 못해요 vs 못 해요
- Bad at / cannot do. Same sound, different spelling.
- Permission
- -아/어도 돼요?: 여기 앉아도 돼요?
- Polite request
- -아/어 주실 수 있어요?: 천천히 말해 주실 수 있어요?
Frequently asked questions
How do you say can in Korean?
Attach -ㄹ 수 있어요 to a stem ending in a vowel (갈 수 있어요) and -을 수 있어요 to a stem ending in a consonant (먹을 수 있어요). It covers both ability and possibility.
What is the difference between 못 and 안?
못 means you cannot, because of ability or circumstances: 오늘은 못 가요. 안 means you do not or will not, by choice: 오늘은 안 가요. When turning down an invitation, 못 sounds softer.
What does -(으)ㄹ 줄 알아요 mean?
It means you know how to do something you have learned: 운전할 줄 알아요, I know how to drive. Its negative is -(으)ㄹ 줄 몰라요.
How do you ask Can I sit here? in Korean?
Use -아/어도 돼요? for permission: 여기 앉아도 돼요? The -(으)ㄹ 수 있어요 form asks whether something is possible, not whether you are allowed.
What is the difference between 못해요 and 못 해요?
Written as one word, 못하다 means to be bad at something: 노래를 못해요, I'm bad at singing. Written with a space, 못 하다 means cannot do: 오늘은 숙제를 못 해요. They sound the same.
- National Institute of Korean Language, Standard Korean Language Dictionary (표준국어대사전): entries for 수, 줄 and 못하다.
- National Institute of Korean Language, Standard Pronunciation Rules (표준 발음법), Article 27: consonants after the -(으)ㄹ modifier ending are pronounced tense, as in 갈 수 [갈쑤].
- National Institute of Korean Language, Basic Korean Dictionary (한국어기초사전): learner entries with example sentences.