-아/어야 하다/되다
Used to express obligation or necessity. It means that an action must be done or a state must be achieved.
Summary
Equivalent
Must / Have to
Example
I have an exam tomorrow, so I have to study.
내일 시험이 있어서 공부해야 해요.
Grammar rules
- Conjugate the verb stem the same way you would for informal present tense (-아/어요) but replace '요' with '-야 하다' or '-야 되다'.
- '되다' is generally more common in spoken Korean.
- For past tense 'had to', conjugate the ending auxiliary ('했다' or '됐다').
어제 공부해야 했어요. (I had to study yesterday.)
Patterns
Verbs with 'ㅏ' or 'ㅗ'
Present · Verb Stem + 아야 하다/되다
Verbs with other vowels
Present · Verb Stem + 어야 하다/되다
하다 Verbs
Present · 해야 하다/되다
Example sentences
I have an exam tomorrow, so I have to study.
내일 시험이 있어서 공부해야 해요.
I'm late for an appointment, so I must go quickly.
약속 시간이 늦어서 빨리 가야 돼요.
You must take the medicine three times a day.
약을 하루에 세 번 먹어야 합니다.
Conversation
A: Do you want to watch a movie together today?
오늘 같이 영화 볼래요?
B: I'm sorry, I have to go home early today.
미안해요, 오늘 일찍 집에 가야 돼요.
Practice
Fill in the blank
Select the correct form to express obligation.
Homework.
Eating.