되다 is a three-in-one chameleon, and the reason it feels slippery to English speakers is that English splits its jobs across four different words. 되다 is the literal "become" (의사가 되다, "become a doctor"); it is the impersonal "turn out / work" (일이 잘 됐어요, "it worked out well"); and it is a modal of permission and prohibition (가도 돼요 "you may go," 먹으면 안 돼요 "you mustn't eat"). One stem doing the work of become / work / may / must-not. On top of the semantics sits the single most notorious spelling problem in Korean — 되 vs 돼 — which this sheet settles with one rule you can apply every time.
The stem at a glance
- Dictionary form: 되다 · stem: 되- · ends in: the vowel ㅚ (no batchim)
- Harmony vowel: 되 + 어 → 돼 (ㅚ + ㅓ → ㅙ). So the polite present is 돼요, past 됐어요.
- Vowel-stem signature: no 으 buffer (되세요, 된, 될, 되면), and the formal present is -ㅂ니다 → 됩니다 [됨니다].
The 되 vs 돼 rule (read this first)
돼 = 되어. Write 돼 only where you could expand it to 되어; everywhere else it stays 되. That is the whole rule, and it never fails:
| Write 돼 (= 되어) when… | Keep 되 when the ending starts with a consonant |
|---|---|
| 돼요 (= 되어요) | 되고 (doego) |
| 됐어요 (= 되었어요) | 되면 (doemyeon) |
| 돼서 (= 되어서) | 되니까 (doenikka) |
| 돼도 (= 되어도) | 되지 (doeji) |
A quick native trick: substitute the verb 하다. Wherever 해 fits, 돼 fits; wherever 하 fits, 되 fits. 해요 → 돼요; 하고 → 되고; 했어요 → 됐어요; 하면 → 되면. 되 : 돼 :: 하 : 해.
Full paradigm: finite forms by speech level
| Mood / tense | 합니다체 (formal) | 해요체 (informal-polite) | 반말 (intimate) | 한다체 (plain / written) |
|---|---|---|---|---|
| Present | 됩니다 doemnida | 돼요 dwaeyo | 돼 dwae | 된다 doenda |
| Present question | 됩니까? doemnikka | 돼요? dwaeyo | 돼? dwae | 되냐? / 되니? doenya / doeni |
| Past | 됐습니다 dwaetseumnida | 됐어요 dwaesseoyo | 됐어 dwaesseo | 됐다 dwaetda |
| Future — 겠 (will / surely) | 되겠습니다 doegetseumnida | 되겠어요 doegesseoyo | 되겠어 doegesseo | 되겠다 doegetda |
| Future — (으)ㄹ 거예요 | 될 겁니다 doel geomnida | 될 거예요 doel geoyeyo | 될 거야 doel geoya | 될 것이다 doel geosida |
| Negative — 안 (won't / must not) | 안 됩니다 an doemnida | 안 돼요 an dwaeyo | 안 돼 an dwae | 안 된다 an doenda |
| Negative — long 지 않다 | 되지 않습니다 doeji anseumnida | 되지 않아요 doeji anayo | 되지 않아 doeji ana | 되지 않는다 doeji anneunda |
| Imperative (blessing / advice) | 되십시오 doesipsio | 되세요 doeseyo | 돼 dwae | 돼라 dwaera |
Because 되다 is often impersonal ("it works out"), its imperative and propositive are limited to well-wishing — 부자 되세요 ("may you get rich," a New Year greeting), 잘돼라 ("may it go well"). You will not command someone to "become" in the way you command them to "go."
저는 커서 수의사가 되고 싶어요.
jeoneun keoseo su-uisaga doego sipeoyo
When I grow up I want to become a vet. (literal 'become'; 되고, consonant ending → 되)
이번 프로젝트 진짜 잘됐어요.
ibeon peurojekteu jinjja jaldwaesseoyo
This project turned out really well. (impersonal 'work out'; 됐 = 되었)
벌써 12시가 됐네요. 얼른 자야겠어요.
beolsseo yeoldusiga dwaenneyo. eolleun jayagesseoyo
It's already 12 o'clock. I should get to bed. (시간이 되다 = a time arrives)
새해 복 많이 받으시고 건강하세요. 부자 되세요!
saehae bok mani badeusigo geonganghaseyo. buja doeseyo
Happy New Year — stay healthy, and may you prosper! (되세요 as a blessing)
Level-invariant forms: connectives and attributives
| Category | Form | Reading | Function |
|---|---|---|---|
| Connective — and | 되고 | doego | "becomes and…" (consonant ending → 되) |
| Connective — so / then | 돼서 | dwaeseo | "becomes and so…" (= 되어서) |
| Connective — if / when | 되면 | doemyeon | "if / when it becomes" |
| Connective — because | 되니까 | doenikka | "since it becomes" |
| Attributive — present | 되는 | doeneun | "(the thing) that becomes / works" |
| Attributive — past | 된 | doen | "(that has) become" (된장, 된밥) |
| Attributive — prospective | 될 | doel | "(that) will become" |
The grammaticalized 되다: come-to, may, must-not
This is where 되다 earns its keep. Four constructions built on the stem carry meanings English handles with modal verbs.
| Pattern | Meaning | Example | Reading |
|---|---|---|---|
| -게 되다 | come to / end up (no one's choice) | 알게 됐어요 | alge dwaesseoyo |
| -아도/어도 되다 | permission — "may / it's OK to" | 가도 돼요 | gado dwaeyo |
| 안 되다 | "won't work / no good / must not" | 안 돼요 | an dwaeyo |
| -(으)면 안 되다 | prohibition — "mustn't" | 먹으면 안 돼요 | meogeumyeon an dwaeyo |
-게 되다 frames an outcome as something that happened to you rather than something you decided — 가게 됐어요 is "I ended up going" (circumstances took me there), not "I chose to go." -아도/어도 되다 grants permission; its mirror image -(으)면 안 되다 withholds it. And bare 안 돼요 is the all-purpose "that won't work / no way / you can't," from a broken vending machine to a firm refusal.
회사 일 때문에 부산에 살게 됐어요.
hoesa il ttaemune busane salge dwaesseoyo
Because of work, I ended up living in Busan. (-게 되다, an outcome I didn't plan)
여기 잠깐 앉아도 돼요?
yeogi jamkkan anjado dwaeyo
Is it OK if I sit here for a moment? (-아도 되다, asking permission)
여기서 사진 찍으면 안 돼요.
yeogiseo sajin jjigeumyeon an dwaeyo
You mustn't take photos here. (-으면 안 되다, prohibition)
이 자판기 고장 나서 안 돼요.
i japangi gojang naseo an dwaeyo
This vending machine is broken, so it's not working. (안 되다 = 'doesn't work')
Common Mistakes
1. Writing ×되요 for the present. 돼요 = 되어요; the bare 되 can't stand as a sentence-ending.
❌ 그렇게 하면 되요.
Wrong — 되어요 contracts to 돼요, so it must be 돼요.
✅ 그렇게 하면 돼요.
geureoke hamyeon dwaeyo
You can just do it that way. (that'll do)
2. Writing ×돼고 / ×돼면 before a consonant ending. No 되어 expansion exists, so keep 되.
❌ 열심히 하면 가수도 돼고 배우도 돼요.
Wrong — before 고 there's no 되어, so it's 되고, not ×돼고.
✅ 열심히 하면 가수도 되고 배우도 돼요.
yeolsimhi hamyeon gasudo doego baeudo dwaeyo
Work hard and you can become both a singer and an actor.
3. Confusing "become X" case-marking. The result of 되다 takes 이/가, not 을/를.
❌ 저는 선생님을 됐어요.
Wrong — the complement of 되다 is marked 이/가: 선생님이 됐어요.
✅ 저는 선생님이 됐어요.
jeoneun seonsaengnimi dwaesseoyo
I became a teacher.
4. Using 안 되다 where you mean simple negation. 안 돼요 = "it won't work / you can't," not "doesn't become."
❌ 저는 아직 어른이 안 돼요.
Odd — for 'haven't become an adult yet' use the plain negative 안 됐어요 / 아직 어른이 아니에요; 안 돼요 reads as 'not allowed.'
✅ 죄송하지만 그건 안 돼요.
joesonghajiman geugeon an dwaeyo
Sorry, but that's not possible / not allowed.
Key Takeaways
- 되다 is a ㅚ vowel stem: 되 + 어 → 돼. Polite 돼요, past 됐어요, formal 됩니다 [됨니다]; no 으 buffer.
- 돼 = 되어 — write 돼 only where 되어 fits (돼요, 됐어요, 돼서); keep 되 before consonant endings (되고, 되면, 되니까). Cross-check with 하/해.
- One stem covers become (의사가 되다), turn out / work (잘 됐어요), and time-arrival (12시가 됐어요).
- The modal life: -게 되다 (end up), -아도 되다 (may), -(으)면 안 되다 (mustn't), and bare 안 돼요 (won't work / no).
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Start learning Korean→Related Topics
- Conjugation Sheet: 하다 (to do)TOPIK 1 — A one-verb cheat sheet for 하다 — the most frequent verb in Korean and the engine behind thousands of noun+하다 verbs (공부하다, 좋아하다, 시작하다). Every cell runs on one contraction: 하 + 여 → 해. Speech levels, tenses, connectives, modifiers, negatives, honorific, imperative, and propositive at a glance.
- -아/어도 되다: May / It's OK ToTOPIK 2 — The permission construction — 'you may, it's OK to, you're allowed to' — built from -아/어도 ('even if you do X') plus 되다 ('it becomes acceptable'), with 괜찮다 and 좋다 as free swaps.
- -(으)면 안 되다: Must Not / Not AllowedTOPIK 2 — The prohibition construction — 'you must not, you're not allowed to' — built as 'if you do X, it doesn't become OK,' the exact negative of the permission pattern -아/어도 되다.
- 돼요 or 되요? The 되다 Spelling TrapTOPIK 2 — 되 + 어 contracts to 돼, so write 돼 before 어/아-endings (돼요, 됐어요) and 되 before consonant-endings (되고, 되면) — with the foolproof 하/해 substitution test.
- Connective Endings by Function (연결어미): Master TableTOPIK 3 — A one-stop table grouping Korean's major clause-connecting endings by meaning — 'and', 'and then', 'but', 'because', 'if', 'in order to', 'even if', 'setting-up' — because Korean chains clauses with verb endings on the first predicate, not with conjunction words.