-아/어야 되다/하다
Have to, Must
-아/어야 되다/하다 means 'must' or 'have to'. It's used to talk about things that are necessary or required.
This pattern also has a main page: -아/어야 하다 (Must/should).
How It Works
This pattern is fundamental for expressing obligation, duty, or necessity in Korean. It's equivalent to 'must', 'have to', or 'should' in English. Both 되다 and 하다 can be used, and they are largely interchangeable, though 되다 is more common in everyday speech.
Conjugation Rules:
The form depends on the last vowel of the verb or adjective stem.
1. Stems with last vowel ㅏ or ㅗ: + -아야 되다/하다
- 가다 (to go) → 가 + 아야 되다 → 가야 되다/하다
- 보다 (to see) → 보 + 아야 되다 → 봐야 되다/하다
- 앉다 (to sit) → 앉 + 아야 되다 → 앉아야 되다/하다
2. Stems with other vowels (ㅓ, ㅜ, ㅡ, ㅣ, etc.): + -어야 되다/하다
- 먹다 (to eat) → 먹 + 어야 되다 → 먹어야 되다/하다
- 읽다 (to read) → 읽 + 어야 되다 → 읽어야 되다/하다
- 만들다 (to make) → 만들 + 어야 되다 → 만들어야 되다/하다
3. Stems ending in 하다: → 해야 되다/하다
- 공부하다 (to study) → 공부해야 되다/하다
- 운동하다 (to exercise) → 운동해야 되다/하다
되다 vs. 하다
While often interchangeable, there's a slight nuance. 되다 can feel like an external or natural requirement ('it has to be done'), while 하다 can imply a stronger sense of personal will or intention ('I must do it'). In most daily conversations, you will hear 되다 more frequently.
Tense and Formality:
This pattern can be conjugated into different tenses and politeness levels.
- Past Tense: 했어야 됐어요 / 했어야 했어요 (I should have done it)
- Formal: 해야 합니다 (I must do it)
- Informal: 해야 돼 (I have to do it)
Examples (5)
- 내일 일찍 일어나야 돼요.
I have to wake up early tomorrow.
Word by Word: Tomorrow early have to wake up.
- 숙제를 오늘까지 끝내야 해요.
I have to finish my homework by today.
Word by Word: Homework by today have to finish.
- 회의 전에 자료를 준비해야 합니다.
I must prepare the materials before the meeting.
Word by Word: Meeting before materials have to prepare (formal).
- 시험에 합격하려면 점수가 좋아야 돼요.
To pass the exam, the score has to be good.
This example shows the pattern used with an adjective (좋다 - to be good).
- 어디로 가야 해요?
Where should I go?
The pattern is commonly used in questions to ask about obligations or what one should do.
Common Mistakes
Confusing obligation (-아/어야 되다) with permission (-아/어도 되다).
Different Meaning지금 가야 돼요? (Asking for permission)Better지금 가도 돼요?-아/어야 되다 means 'must/have to' (obligation). Asking '가야 돼요?' sounds like 'Do I have to go?'. To ask for permission ('May I go?'), you should use -아/어도 되다.
Incorrectly conjugating 하다 verbs.
Not Quite공부하어야 해요.Better공부해야 해요.Verbs ending in 하다 always contract to 해야. The form 하 + 어야 becomes 해야.
Learn This First
To express 'have to/must', you need necessity patterns and auxiliary verbs.
Related Patterns
- -(으)면 안 되다Must Not, Should Not
This pattern expresses prohibition, meaning 'must not' or 'should not'. While -아/어야 되다/하다 expresses a positive obligation (what you must do), -면 안 되다 expresses a prohibition (what you must not do).
- -아/어도 되다May, Be Allowed to
This pattern expresses permission ('may', 'it is okay to'), which is the opposite of obligation. Learners often confuse these two. -아/어야 되다/하다 is for things you have to do, and -아/어도 되다 is for things you are allowed to do.
- -지 않아도 되다Don't Have to, Not Necessary
This expresses a lack of necessity ('don't have to'). -지 않아도 되다 is the negation of the obligation itself. For example, '가야 돼요' means 'You have to go,' while '가지 않아도 돼요' means 'You don't have to go.'
- -아/어야겠다I Should, I Need to
Similar in meaning, but -아/어야겠다 expresses a personal realization or decision that one 'should' or 'must' do something. It's more about a speaker's immediate thought or intention, like 'I guess I should...' or 'I'd better...'.