Korean Grammar -(으)ㄹ걸: How to Say “I Should Have”

What does -(으)ㄹ걸 mean in Korean?

In this Korean grammar lesson, you’ll learn how to use -(으)ㄹ걸 to express regret about something you did or didn’t do.

For example:

이를 닦을걸.

I should’ve brushed my teeth.

Why would someone regret not brushing their teeth?

Well… she kissed a vampire after eating garlic bread. 🧛‍♂️🧄

Let’s start from the beginning.

Learn -(으)ㄹ걸 Through a Korean Vampire Story

Our story begins with a rather serious confession.

나… 사실 뱀파이어야.

I’m… actually a vampire.

Luckily for him, she takes the news surprisingly well.

인간이 아니어도 상관없어.

I don’t care if you’re not a human.

And then:

뱀파이어여도 상관없어.

I don’t care if you’re a vampire.

So far, so good.

She loves him. He loves her.

They kiss.

And then…

Our vampire is down. What happened?

내가 뭘 잘못했지?

What did I do wrong?

Then she remembers.

아까 마늘빵을 먹었구나.

Oh, I had garlic bread earlier.

Oops. 🧄 And now she has one major regret:

이를 닦을걸.

I should’ve brushed my teeth.

Unfortunately, the realization comes a little too late. 😂

What Does -(으)ㄹ걸 Mean in Korean?

-(으)ㄹ걸 is used to express regret about something you did or didn’t do. It often corresponds to “I should have…” in English.

The basic pattern is:

Verb stem + -(으)ㄹ걸

After a vowel or ㄹ, use -ㄹ걸:

가다 → 갈걸

집에 갈걸.

I should have gone.

벌다 → 벌걸

돈을 많이 벌걸.

I should have made lots of money.

After another consonant, use -을걸:

먹다 → 먹을걸

천천히 먹을걸.

I should have eaten slowly.

입다 → 입을걸

바지를 입을걸.

I should have put on pants.

말다 → 말걸

낮잠 자지 말걸.

I shouldn't have taken a nap.

Here are a few more natural examples:

우산 가져올걸.

I should’ve brought an umbrella.

일찍 잘걸.

I should’ve gone to bed early.

다른 거 먹을걸.

I should’ve eaten something else.

When Do Koreans Use -(으)ㄹ걸?

Koreans often use -(으)ㄹ걸 when thinking to themselves or talking to themselves about something they regret.

It’s especially natural when you realize afterward that you wish you had done something differently.

Imagine that you leave home without an umbrella. Then it starts raining.

우산 가져올걸.

I should’ve brought an umbrella.

You stay up too late and feel terrible the next morning.

일찍 잘걸.

I should’ve gone to bed early.

Or you see someone else’s food at a restaurant and suddenly regret your order.

다른 거 시킬걸.

I should’ve ordered something else.

These sentences don’t necessarily have to be directed at another person. You might simply think them in your head or mutter them to yourself when you realize you made the wrong choice.

That’s exactly what happens in our vampire story:

이를 닦을걸.

I should’ve brushed my teeth.

She isn’t really telling anyone what she should have done. She’s realizing her mistake and expressing her regret to herself.

That’s an important part of understanding how this Korean grammar pattern feels in real life: it often sounds like an afterthought that comes with a little—or sometimes a lot of—regret.

What Other Korean Expressions Appear in the Toon?

There are a few more pieces of natural Korean hiding in our vampire tragedy.

What Does 털썩 Mean in Korean?

털썩 is a Korean mimetic word that describes someone or something suddenly collapsing, dropping, sitting down, or sinking down heavily.

In our story, the kiss happens and then—

털썩!

The vampire collapses.

Words like 털썩 are especially common in Korean comics and webtoons because they make an action feel almost visible or audible.

What Is 뭘 Short For?

When the vampire collapses, she asks:

뭘 is a common contracted form of 무엇을.

For example:

뭘 갖고 가야 해?

What should I bring?

You’ll hear 뭘 frequently in everyday spoken Korean.

What Does -(이)어도 상관없다 Mean?

Earlier, our heroine says:

뱀파이어여도 상관없어.

I don’t care if you’re a vampire.

Here, 여도 is a contraction of 이어도.

The pattern (이)어도 상관없다 means that something is okay or doesn’t matter even if it is something.

For example:

학생이어도 상관없어요.

It’s okay even if you’re a student.

And in our story:

뱀파이어여도 상관없어.

I don’t care if you’re a vampire.

Apparently, being a vampire wasn’t the problem.

The garlic bread was. 🧄

Is “Vampire” 뱀파이어 or 흡혈귀 in Korean?

Both 뱀파이어 and 흡혈귀 mean “vampire” in Korean.

But that raises another interesting question: Which one do Koreans actually use more these days?

🧛 vampire: 뱀파이어 vs. 흡혈귀

And the same question came up with another word in this toon:

🧄 garlic bread: 마늘빵 vs. 갈릭 브레드

I got curious, so I compared Korean search data for both pairs.

The search data shows a clear preference: 뱀파이어 is searched far more often than 흡혈귀, and 마늘빵 is searched far more often than 갈릭 브레드.

That doesn’t mean 흡혈귀 or 갈릭 브레드 are incorrect. All four words exist in Korean. But search trends can give us a useful glimpse into which terms people are more likely to look for online today.

And that’s one of the interesting things about modern Korean: sometimes an English-derived word like 뱀파이어 becomes more prominent, while in other cases, the Korean word 마늘빵 remains much more common in search.

So if you’re learning Korean, don’t be surprised when you encounter more than one word for the same thing. Language changes, preferences shift, and the word you learned in a textbook may not always be the one you encounter most often in everyday life.

And in this particular story, there’s only one word our vampire really needed to worry about:

마늘. 🧄 😂

Why Learn Korean Grammar Through Stories?

You could memorize:

-(으)ㄹ걸 = “should have / shouldn’t have”

Or you could remember a woman crying beside her vampire boyfriend’s coffin because she forgot to brush her teeth after eating garlic bread. 😂

A story gives grammar something to attach itself to: a character, a situation, an image, and a consequence.

The next time you encounter -(으)ㄹ걸, you’re not just trying to retrieve a grammar rule. You have a vampire, a kiss, garlic bread, and one very unfortunate ending to help you remember it.

That’s why I create Korean-learning comics like this—and why I use the same approach in my books.

I write K-drama-style bilingual novels specifically for Korean learners, combining stories you actually want to keep reading with Korean vocabulary, grammar, and everyday expressions you can learn along the way.

You can browse my books on my author page and read free samples.

No Fun, No Learning. ❤️

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About the Author

Saehee Um is a Korean language professional, author, and founder of ToonToon Korean. She creates bilingual Korean reading materials and K-drama-style novels that help Korean learners experience vocabulary, expressions, and culture through stories, context, and repeated exposure.