How to Say "Can" and "Cannot" in Korean: ~(으)ㄹ 수 있다/없다

At some point in every Korean learner's journey, you need to say what you can and cannot do.

"I can speak Korean." "I can't eat spicy food." "Can you come tomorrow?"

In Korean, one pattern handles all of this: ~(으)ㄹ 수 있다/없다. It's one of the most useful A2 grammar patterns - and once you have it, a huge range of real conversations opens up.

What Does ~(으)ㄹ 수 있다/없다 Mean?

수 literally means "way" or "means" - so the pattern is saying "there is a way to do [verb]" or "there is no way to do [verb]." Over time, this became the standard expression for ability and possibility.

How to Form ~(으)ㄹ 수 있다/없다

Step 1: Remove 다 from the dictionary form → get the verb stem Step 2: Add (으)ㄹ - same rule as future tense:

For 없어요, just swap 있어요:

갈 수 없어요 / 먹을 수 없어요 / 만들 수 없어요

Conjugation Table

💡 듣다 is a ㄷ irregular — ㄷ→ㄹ before vowel: 들 + 을 수 있어요 = 들을 수 있어요

~(으)ㄹ 수 있어요 in Real Sentences

🗣️ Language & Skills

한국어를 할 수 있어요.

• Literal: Korean [object] do can
• Natural: I can speak Korean.

한국어를 조금 읽을 수 있어요.

• Natural: I can read Korean a little.

한자를 읽을 수 없어요.

• Natural: I can't read Chinese characters.

피아노를 칠 수 있어요?

• Natural: Can you play the piano?

수영을 배운 적이 없어서 수영할 수 없어요.

• Natural: I've never learned to swim, so I can't swim.

🍽️ Food & Preferences

매운 음식을 먹을 수 있어요?

• Natural: Can you eat spicy food?

저는 매운 것을 잘 먹을 수 있어요.

• Natural: I can eat spicy things well.

술을 마실 수 없어요. 알레르기가 있어요.

• Natural: I can't drink alcohol. I have an allergy.

이 식당에서 채식 음식을 먹을 수 있어요?

• Natural: Can I eat vegetarian food at this restaurant?

📅 Plans & Availability

내일 올 수 있어요?

• Natural: Can you come tomorrow?

오늘은 갈 수 없어요. 일이 있어요.

• Natural: I can't go today. I have things to do.

이번 주말에 만날 수 있어요?

• Natural: Can we meet this weekend?

지금 당장은 도와드릴 수 없어요.

• Natural: I can't help you right away.

🌍 Ability & Experience

운전할 수 있어요?

• Natural: Can you drive?

네, 운전할 수 있어요. 10년 됐어요.

• Natural: Yes, I can drive. It's been 10 years.

혼자 살 수 있을 것 같아요.

• Natural: I think I can live alone.

여기에서 와이파이를 쓸 수 있어요?

• Natural: Can I use WiFi here?

Past Tense: Could / Couldn't

To talk about past ability, use 있었어요 / 없었어요:

Future: Will Be Able To

For future ability, combine with 것 같다 or simply use context:

연습하면 할 수 있을 거예요. If you practice, you'll be able to do it.

내일까지 끝낼 수 있을 것 같아요. I think I'll be able to finish by tomorrow.

못 - The Shorter Alternative for "Cannot"

Korean has another way to express inability: 못 placed before the verb.

Both mean the same thing - but with slightly different nuances:

In everyday speech, 못 is more common in casual conversation. ~(으)ㄹ 수 없어요 feels slightly more formal or emphatic.

💡 하다 verbs with 못: Same rule as 안 - 못 goes between noun and 하다: 운동 못 해요 (I can't exercise) 공부 못 해요 (I can't study)

Real Conversations Using ~(으)ㄹ 수 있다/없다

📍 Conversation 1: Making plans

A: 이번 주말에 같이 등산 갈 수 있어요? (Can you go hiking together this weekend?)

B: 토요일은 갈 수 없어요. 약속이 있어요. (I can't go on Saturday. I have plans.)

A: 일요일은요? (What about Sunday?)

B: 일요일은 갈 수 있어요! 몇 시에 만날까요? (I can go on Sunday! What time shall we meet?)

📍 Conversation 2: Asking about abilities

A: 한국어 할 수 있어요? (Can you speak Korean?)

B: 네, 조금 할 수 있어요. 아직 많이 부족해요. (Yes, I can speak a little. I still have a long way to go.)

A: 어디에서 배웠어요? (Where did you learn?)

B: 온라인 코스로 배웠어요. 한자는 읽을 수 없지만 한글은 읽을 수 있어요. (I learned through an online course. I can't read Chinese characters, but I can read Hangul.)

📍 Conversation 3: At a restaurant

A: 저 견과류 알레르기가 있어요. 이 요리에 견과류가 들어가요? (I have a nut allergy. Does this dish contain nuts?)

B: 잠깐만요, 확인해 드릴게요. (One moment, I'll check for you.)

B: 죄송합니다. 이 요리는 드실 수 없을 것 같아요. 견과류가 들어가요. (I'm sorry. I don't think you'll be able to eat this dish. It contains nuts.)

A: 괜찮아요. 다른 것 먹을게요. (That's okay. I'll eat something else.)

Common Mistakes to Avoid

❌ Mistake 1: Forgetting 을 after a consonant stem

❌ 먹 수 있어요 ✅ 먹을 수 있어요

❌ Mistake 2: Using 수 있어요 with adjectives

~(으)ㄹ 수 있다 is for action verbs — things you do. Don't use it with adjectives.

❌ 예쁠 수 있어요. (wrong) ✅ 예뻐요. / 예뻐질 수 있어요. (can become pretty)

❌ Mistake 3: Confusing 안 and 못

안 가요 = I don't go (choice) 못 가요 = I can't go (inability/circumstance) 갈 수 없어요 = I can't go (ability/possibility)

Quick Practice

Translate using ~(으)ㄹ 수 있어요 or ~(으)ㄹ 수 없어요:

1. I can drive.
2. I can't eat raw fish.
3. Can you come tomorrow?
4. I could speak Korean a little.
5. I think I'll be able to finish.

Answers:

1. 운전할 수 있어요.
2. 회를 먹을 수 없어요.
3. 내일 올 수 있어요?
4. 한국어를 조금 할 수 있었어요.
5. 끝낼 수 있을 것 같아요.

Summary

~(으)ㄹ 수 있다/없다 is one of those patterns you'll use every single day. Ability, permission, possibility - it covers them all. And once it's in your toolkit, conversations that once felt out of reach suddenly become manageable.