-(으)면 안 되다
must not, is not allowed
The refusal half of the permission pair. Literally “if you do it, it won’t do” — a rule stated impersonally rather than an order aimed at one person.
Build it
Pick a verb
When to use it
Attachment is the ordinary -(으)면 rule, and ㄹ stems keep their ㄹ: 만들다 gives 만들면 안 돼요.
It states a prohibition as a fact about the world rather than a request from you: 여기에서 담배를 피우면 안 돼요 reads as “smoking here isn’t allowed.” Compare -지 마세요, which is you personally asking someone to stop.
Its most common job is answering a permission question in the negative, because -아/어도 되다 cannot simply be negated. Be careful with the alternative that looks similar: 안 -아/어도 되다 means “you don’t have to,” which is the opposite of forbidding.
How to attach it
| Stem type | Form | Example |
|---|---|---|
| Ends in a vowel | -면 안 되다 | 가다 → 가면 안 돼요 |
| Ends in a consonant | -으면 안 되다 | 먹다 → 먹으면 안 돼요 |
| Ends in ㄹ | ㄹ stays | 만들다 → 만들면 안 돼요 |
| Formal | -(으)면 안 됩니다 | 들어가면 안 됩니다 |
| Direct request instead | -지 마세요 | 들어가지 마세요 |
| Not required | 안 -아/어도 되다 | 안 가도 돼요 |
In use
여기에서 담배를 피우면 안 돼요.
You mustn’t smoke here.
시험 중에 이야기하면 안 됩니다.
Talking is not permitted during the exam.
이 문을 열면 안 돼요.
You mustn’t open this door.
약속을 잊으면 안 돼요.
You mustn’t forget the appointment.
들어가도 돼요? — 아니요, 들어가면 안 돼요.
May I go in? — No, you may not.
늦으면 안 되니까 지금 출발합시다.
We mustn’t be late, so let’s leave now.
Compared with
-지 마세요
-지 마세요 is a request from you to the listener; -(으)면 안 되다 reports a rule. Signs and regulations use the second; a friend asking you to stop uses the first.
여기에 주차하지 마세요. (I’m asking) / 여기에 주차하면 안 돼요. (it’s not allowed)
-아/어도 되다
The pair works as question and refusal, but the construction changes between them. This asymmetry is the single most common error with permission in Korean.
가도 돼요? → 네, 가도 돼요. / 아니요, 가면 안 돼요.
-아/어야 되다
Obligation and prohibition are opposites: one says you have to, the other says you must not. Note that “you don’t have to” is neither — that is 안 -아/어도 되다.
가야 돼요. (you have to go) / 가면 안 돼요. (you must not go) / 안 가도 돼요. (you don’t have to go)
Watch out
이 음식을 만들으면 안 돼요.
이 음식을 만들면 안 돼요.
A stem ending in ㄹ keeps it and adds nothing, exactly as with plain -(으)면.
안 가면 돼요. — meaning “you must not go”
가면 안 돼요.
Moving the 안 changes the meaning to “it’s fine if you don’t go.” The negation belongs on 되다, not on the main verb.
숙제를 안 하면 안 돼요? — asking permission to skip it
숙제를 안 해도 돼요?
Double negatives are grammatical here but confusing. To ask whether something can be skipped, use 안 -아/어도 되다.
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