-(으)ㄹ 줄 알다/모르다
know how to / not know how to
Reports a learned skill. Built from the future modifier plus 줄, a noun meaning “method” — and the same shape has a second, unrelated meaning that catches everyone.
Build it
Pick a verb
When to use it
Attachment is the standard rule, with the ㄹ short form: 만들다 gives 만들 줄 알아요. 줄 is a noun, so it stands as its own word.
It is specifically about knowing how — a skill acquired by learning: swimming, driving, cooking, playing an instrument, speaking a language. For possibility or permission, Korean uses -(으)ㄹ 수 있다 instead.
Now the trap. In the past, -(으)ㄹ 줄 알았다 usually does not mean “I knew how to.” It means I thought it would be so, and typically introduces a mistaken assumption: 비가 올 줄 알았어요 — I thought it would rain (but it didn’t). Context decides, but this reading is far more common.
How to attach it
| Stem type | Form | Example |
|---|---|---|
| Ends in a vowel | -ㄹ 줄 알다 | 하다 → 할 줄 알아요 |
| Ends in a consonant | -을 줄 알다 | 읽다 → 읽을 줄 알아요 |
| Ends in ㄹ | nothing added | 만들다 → 만들 줄 알아요 |
| Cannot do it | -(으)ㄹ 줄 모르다 | 할 줄 몰라요 |
| Spacing | 줄 is a separate word | 할 줄 알아요 — not 할줄 |
| Past = assumption | -(으)ㄹ 줄 알았다 | 비가 올 줄 알았어요 |
In use
저는 수영할 줄 알아요.
I know how to swim.
한국 음식을 만들 줄 알아요?
Do you know how to cook Korean food?
아직 운전할 줄 몰라요.
I don’t know how to drive yet.
한글은 읽을 줄 아는데 뜻은 몰라요.
I can read Hangul, but I don’t know what it means.
오늘 비가 올 줄 알았어요.
I thought it was going to rain today.
그 사람이 올 줄 몰랐어요.
I had no idea he would come.
Compared with
-(으)ㄹ 수 있다
수 있다 covers ability and circumstance alike; 줄 알다 is only about a skill you learned. For “I can go tomorrow,” only 수 있다 works.
수영할 줄 알아요. (I know how) / 내일 갈 수 있어요. (I’m able to go)
못
못 says a particular attempt was blocked; 줄 모르다 says the skill was never acquired.
수영할 줄 몰라요. (I never learned) / 오늘은 수영 못 해요. (I can’t today)
-(으)ㄹ 줄 알았다 as assumption
The past form almost always means “I assumed.” To say you knew how to do something in the past, Korean prefers 할 수 있었어요 or rewording.
비가 올 줄 알았어요. (I thought it would rain) / 그때는 수영할 수 있었어요. (I could swim back then)
Watch out
한국 음식을 만들을 줄 알아요.
한국 음식을 만들 줄 알아요.
A stem ending in ㄹ already supplies it, as with 만들 수 있다 and 만들 거예요.
저는 수영할 줄 있어요.
저는 수영할 줄 알아요.
줄 pairs with 알다 and 모르다, not with 있다. 수 pairs with 있다 and 없다. Keep the two constructions apart.
내일 갈 줄 알아요. — meaning “I can go tomorrow”
내일 갈 수 있어요.
Going somewhere is not a learned skill. Reserve 줄 알다 for abilities you had to acquire.
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