jabi-어야 되다
-아/어야 되다: Have To, and the 하다 Twin
Have to, must — states an obligation or a necessary condition.
How to form it
| When | Form | Example |
|---|---|---|
| Stem vowel is ㅏ or ㅗ | -아야 되다 | 가다 → 가야 돼요 |
| Any other vowel | -어야 되다 | 먹다 → 먹어야 돼요 |
| 하다 verbs | -해야 되다 | 공부하다 → 공부해야 돼요 |
| With 하다 instead | -어야 하다 | 가야 해요 (slightly more written) |
| Past | -어야 했다 / 됐다 | 가야 했어요 |
-아/어야 되다 is how you say you have to do something. It is one of the highest-frequency patterns in everyday Korean.
Building it
Same vowel decision you already make for 해요체.
ㅏ or ㅗ → -아야 되다
anything else → -어야 되다
하다 → -해야 되다
가다 → 가야 돼요 I have to go
먹다 → 먹어야 돼요 I have to eat
공부하다 → 공부해야 돼요Once 해요체 is automatic, this costs nothing new.
돼요, not 되요
되 + 어요 → 돼요. The contraction is obligatory.
가야 돼요. ✅
가야 되요. ✗This is worth flagging because native speakers get it wrong constantly — you will see 되요 in messages, captions and signs. It is still a misspelling, and getting it right is an easy way to look careful in writing.
The test Koreans use: if you can substitute 해, write 돼. 가야 해요 works, so 가야 돼요.
되다 or 하다
Both exist:
가야 돼요.
가야 해요.
| -어야 되다 | more common in speech |
| -어야 하다 | slightly more written and formal |
Some speakers report a faint difference — 하다 feeling more like an obligation you hold yourself to, 되다 more like a condition of the situation. It is subtle enough that you can use either and nobody will notice.
The 되다 family
This construction has two siblings, and learners mix them up:
| Meaning | |
|---|---|
| -아/어야 되다 | have to |
| [[g:eodo-doeda | -아/어도 되다]] |
| [[g:eumyeon-doeda | -(으)면 되다 / 안 되다]] |
Watch what the negatives do:
가야 돼요. I have to go.
안 가도 돼요. I don't have to go. ← obligation removed
가면 안 돼요. I must not go. ← prohibitionRemoving an obligation and forbidding something are different constructions. Translating “don’t have to” straight from English produces 가지 않아야 돼요, which is not how Korean expresses it.
Past
어제 일찍 가야 했어요. — I had to leave early yesterday.
예약을 해야 됐어요. — I had to make a reservation.
Both 했어요 and 됐어요 work, matching the present-tense choice.
Sentences worth having ready
| 가야 돼요 | I have to go |
| 지금 가야 돼요? | Do I have to go now? |
| 꼭 해야 돼요 | You definitely have to do it |
| 안 해도 돼요 | You don’t have to |
| 내일까지 끝내야 돼요 | I have to finish it by tomorrow |
Shopping-list talk in the same Sejong unit often softens with -고요 — 카드도 사고요 — after the obligation is clear.
Do not confuse it with
Taught alongside this
In the Sejong course this appears in 집들이에 뭘 사 가야 돼요? — Sejong Korean 1, Unit 17, on the theme of 집들이. These come with it:
Words used above
Quick check
No sign-up, no score saved — just see if it stuck.
1. What is 먹다 in this form?
2. Which is written as 돼요 and which as 되요?
3. What does 안 가도 돼요 mean?
Common questions
Is there a difference between -어야 되다 and -어야 하다?
Very little. 되다 is more common in speech, 하다 slightly more written and formal. Some speakers feel 하다 is a shade more about internal obligation, but nobody will correct you either way.
How do I say 'don't have to'?
안 …아/어도 되다 — 안 가도 돼요, you don't have to go. Removing an obligation is a different construction from forbidding something.
How do I say 'must not'?
-(으)면 안 되다 — 가면 안 돼요. Full pair with 'it's enough if' lives on [[g:eumyeon-doeda]].
Why 돼요 and not 되요?
되 + 어요 → 돼요. The contraction is required. 되요 is simply a misspelling, though you will see it written by native speakers constantly.
Seen in the wild
Lessons where this pattern showed up in real Korean — news, slang, drama lines.