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How to say “should” and “should not” in Korean |

It's KoreanStudyJunkie and in this lesson we'll look at 5 different Korean grammar structures that you'll hear and also use a lot. Although, they can be a bit confusing. There's a short practice section at the end so stick around.

V + 아/어야 되다 / 아/어야 하다 = should, have to, must

Usage: to express that It’s a necessity to do something or an obligation. The use of -아/어야 되다 is more commonly used than -아/어야 하다, but they mean the exact same. 아/어야 되다 has 2 negative forms that we’ll learn a little more about later in the post.

1.) -지 않아도 되다 = not necessary to do something

2.)-(으)면 안 되다 = prohibition of some behavior

Verb stem ending in vowel ㅏ or ㅗ + 아야 되다/하다

Verb stem ending in vowel other than ㅏ or ㅗ + 어야 되다/하다

하다 Verbs → 해야 되다/하다


내일 시험이 있어요. 그래서 공부해야 돼요. =I have an exam tomorrow. So I must study.

회사에 가야 해요. = I have to go to work.

대학교에 가고 싶다면 열심히 공부해야 해요. = If you want to go to University, you must study hard

아/어/해야 지(요) = I should, will do, must do

Usage: Express speaker’s strong intention like a promise to oneself or a decision to do something. An expression used to indicate the speaker's determination or will. Used to think or speak to oneself, informal form V-아/어야지 is used.


그 영화가 너무 재미있다고 했어. 나도 봐야지. = I heard that the movie is very interesting. I will see it, too.

내일이 시험이니 오늘은 공부를 해야지요. = I have an exam tomorrow, so I have to study today.

아/어야 겠지 may also be used for a similar meaning

(으)면 안 되다 = should not, may not, not allowed to

Usage: attaches to verb stem to prohibit some behavior, say one should/must not do something, or ask someone else for permission to do something.

~(으)면 안 되다 can be used in the form of a question. One is asking if there will be a “problem” if the action before ~(으)면 occurs. Translated like “May I..?” “Is it okay if…” “Can/can’t you…?”


길에 쓰레기를 버리면 안 돼요.

You’re not allowed to throw trash on the street.

박물관에서 사진을 찍으면 안 돼요.

You may not take pictures in the museum.

(으)면 되다 = suggesting that one should

Usage: By adding ~(으)면 되다 to the end of a sentence or clause, the meaning is similar to ~아/어야 되다, using ~(으)면 되다 is more of a suggestion or to simply mean that if a certain condition is fulfilled, it’s enough.

It’s not emphasizing the necessity to do. or an obligation to do something. Because this is more of a suggestion, its meaning is very soft and is often used by people when they are asked for advice.

Example vs Example:

9시까지 와야 돼요. = You have to be here by 9.

9시까지 오면 돼요. = You can come by 9.

-아/어도 되다 = may, can I..?

Usage: this is used to ask someone for approval or permission. This translates to “one may” or “one is allowed to.” V-아/어도 되다 can be replaced by -아/어도 괜찮다, -아/어도 좋다 without meaning change.

This grammar is similar to (으)면 안 되다. There doesn’t seem to be a big difference between this grammar and 면 안 되다, the only small thing seems to be that (으)면 되다 can be used to talk about yourself, but 아/어/여도 되다 is used mainly for talking to other people for asking “permission” sake.


제가 일찍 가도 돼요?  = May I go early?

지금 문을 열어도 돼요  = You may open the door now.


Translate a sentence using grammar from the post

1.) I should do my homework now

2.) It’s okay If you don’t study everyday

3.) My brother is not allowed to watch tv this week.



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