Lesson 25: 아/어/여야 돼요

Korean Lesson Title

In this lesson, you will learn how to use the structure 아/어/여야 돼요 to express the idea of obligation or necessity. By the end of this lesson, you will be able to say things like “I must study.“, “You should learn Korean.“, etc.

Lesson 25: 아/어/여야 돼요

The structure 아/어/여야 돼요 is similar to ‘have to’, ‘should’, ‘need to’ or ‘must’ in English. 아/어/여야 돼요 is used to express the idea of obligation or necessity. Let’s look at some examples.

가다 = to go
가야 돼요 = have to go
학교에 가야 돼요. = I have to go to school.

먹다 = to eat
먹어야 돼요 = should eat
지금 점심을 먹어야 돼요. = I should eat my lunch now.

공부하다 = to study
공부해야 돼요 = must study
오늘 공부해야 돼요. = I must study today.

The structure 아/어/여야 돼요 is made up of the ending 아/어/여야 and the verb 돼요. 아/어/여야 means ‘only when ~’. And 돼요 is the present form of the verb 되다 which means ‘to function/work’ or ‘to be okay’. So, it literally means ‘Only when you do it, it will be okay.’

Conjugation Rules

Conjugation RuleExample
Last vowel in verb stem is ㅏ or ㅗ
+ 아야 돼요
가야 돼요 (should go)
Last vowel in verb stem is NOT ㅏ or ㅗ
+ 어야 돼요
먹어야 돼요 (should eat)
Verb ends in 하다
+ 여야 돼요
공부해야 돼요 (should study)

In the structure 아/어/여야 돼요, the verb 돼요 can be replaced with 해요. 아/어/여야 해요 sounds more formal and it’s commonly used in written language. For example, “I should exercise” can be expressed as 운동해야 돼요 (less formal, spoken language) or as 운동해야 해요 (slightly formal, written language).

Example Sentences

오늘 뭐 할 거예요? = What are you going to do today?
공부해야 돼요. 내일 시험이 있어요. = I must study. I have an exam tomorrow.

어디에 가요? = Where are you going?
백화점에 가요. 옷을 사야 돼요. = I’m going to the department store. I need to buy clothes.

지금 같이 점심 먹을까요? = Shall we eat lunch together now?
미안해요. 친구를 만나야 돼요. = Sorry. I have to meet my friend.