-(으)니까 expresses strong causation where the first clause is the reason for the second clause. It emphasizes "since/because" with a focus on the resulting action or state.
Structure
Verb/Adjective stem + -(으)니까
Breakdown:
- -(으)니까: Causal ending
- Emphasizes reason → consequence relationship
Literal meaning: "Since/because [reason], [result]"
Formation Rules
Stems Ending in Vowel: -니까
No final consonant:
- 가다 → 가니까 (since/because go)
- 오다 → 오니까 (since/because come)
- 크다 → 크니까 (since/because big)
- 바쁘다 → 바쁘니까 (since/because busy)
Stems Ending in Consonant: -으니까
Has final consonant:
- 먹다 → 먹으니까 (since/because eat)
- 읽다 → 읽으니까 (since/because read)
- 좋다 → 좋으니까 (since/because good)
- 작다 → 작으니까 (since/because small)
ㄹ Irregular: Drop ㄹ + -니까
Stems ending in ㄹ:
- 살다 → 사(ㄹ)니까 → 사니까 (since/because live)
- 만들다 → 만드니까 (since/because make)
- 팔다 → 파니까 (since/because sell)
하다 Verbs: -하니까
All 하다 verbs:
- 공부하다 → 공부하니까 (since/because study)
- 바쁘다 → 바쁘니까 (since/because busy)
- 피곤하다 → 피곤하니까 (since/because tired)
Core Meaning: Strong Causation
Objective Reasons
Factual, observable causes:
- 비가 오니까 우산을 가져가요 (Since it's raining, take an umbrella)
- 늦었으니까 택시 타요 (Since we're late, let's take a taxi)
- 배고프니까 먹어요 (Since you're hungry, eat)
Commands and Suggestions
-(으)니까 often precedes imperatives/proposals:
- 좋으니까 사세요 (It's good, so buy it)
- 비싸니까 사지 마세요 (It's expensive, so don't buy it)
- 위험하니까 조심하세요 (It's dangerous, so be careful)
Discovered Reasons
Realizing a cause:
- 아, 오늘 일요일이니까 쉬어요 (Oh, it's Sunday, so they're closed)
- 여기가 명동이니까 비싸요 (This is Myeongdong, so it's expensive)
- 지금 점심시간이니까 사람이 많아요 (It's lunch time, so there are many people)
Common Usage Patterns
Making Suggestions
Based on reasons:
- 날씨가 좋으니까 나가요 (The weather is nice, so let's go out)
- 시간 있으니까 천천히 해요 (We have time, so let's do it slowly)
- 어려우니까 도와줄게요 (It's difficult, so I'll help you)
Giving Commands
Justifying orders:
- 늦었으니까 빨리 가세요 (It's late, so go quickly)
- 아프니까 쉬세요 (You're sick, so rest)
- 위험하니까 하지 마세요 (It's dangerous, so don't do it)
Explaining Situations
Providing context:
- 오늘 금요일이니까 사람이 많을 거예요 (It's Friday, so there will be many people)
- 여기 유명하니까 맛있을 거예요 (This place is famous, so it will be delicious)
- 지금 겨울이니까 춥죠 (It's winter now, so it's cold, right?)
Tense with -(으)니까
Present Tense: -(으)니까
Current state/habitual:
- 비싸니까 안 사요 (It's expensive, so I won't buy it)
- 좋으니까 추천해요 (It's good, so I recommend it)
Past Tense: -았/었으니까
Past reason for current/future action:
- 많이 먹었으니까 이제 그만 먹어요 (I ate a lot, so let's stop now)
- 공부했으니까 잘 할 거예요 (I studied, so I'll do well)
- 약속했으니까 꼭 가야 해요 (I promised, so I must go)
Future Tense: -(으)ㄹ 거니까
Future reason (less common):
- 늦을 거니까 먼저 가세요 (I'll be late, so go first)
- 비쌀 거니까 준비하세요 (It will be expensive, so prepare)
Common Expressions
Daily Reasons
- 배고프니까 밥 먹어요 (I'm hungry, so let's eat)
- 피곤하니까 쉬어요 (I'm tired, so let's rest)
- 춥니까 옷 입으세요 (It's cold, so wear clothes)
- 더우니까 창문 열어요 (It's hot, so open the window)
Polite Refusals
- 바쁘니까 다음에 만나요 (I'm busy, so let's meet next time)
- 지금 안 되니까 나중에 해요 (I can't now, so let's do it later)
- 약속이 있으니까 먼저 갈게요 (I have an appointment, so I'll leave first)
Strong Advice
- 위험하니까 조심하세요 (It's dangerous, so be careful)
- 중요하니까 잊지 마세요 (It's important, so don't forget)
- 어려우니까 천천히 하세요 (It's difficult, so do it slowly)
Politeness Levels
Formal (합니다체)
- 비가 오니까 우산을 가져가십시오 (It's raining, so please take an umbrella)
- 늦었으니까 서두르십시오 (It's late, so please hurry)
Polite (해요체)
- 좋으니까 한번 해 보세요 (It's good, so try it once)
- 비싸니까 생각해 보세요 (It's expensive, so think about it)
Casual (반말)
- 재미있으니까 봐 봐 (It's fun, so watch it)
- 맛있으니까 먹어 봐 (It's delicious, so try it)
Negative Forms
Negative Reason
안 + Verb + -(으)니까:
- 안 좋으니까 하지 마세요 (It's not good, so don't do it)
- 안 비싸니까 사세요 (It's not expensive, so buy it)
Verb + -지 않으니까:
- 좋지 않으니까 바꾸세요 (It's not good, so change it)
- 비싸지 않으니까 괜찮아요 (It's not expensive, so it's okay)
Can't/Unable
못 + Verb + -(으)니까:
- 못 가니까 미안해요 (I can't go, so I'm sorry)
- 못 먹으니까 다른 거 주세요 (I can't eat it, so please give me something else)
-(으)니까 vs Similar Patterns
-(으)니까 vs -아/어서
-(으)니까: Stronger causation, can use with commands
- 비싸니까 사지 마세요 (It's expensive, so don't buy it) ✅
-아/어서: Softer causation, CANNOT use with commands
- 비싸서 사지 마세요 ❌ (Grammatically incorrect)
- 비싸서 안 샀어요 (It was expensive, so I didn't buy it) ✅
-(으)니까 vs -면
-(으)니까: Because/since (reason-result)
- 비가 오니까 집에 있어요 (Since it's raining, stay home)
-면: If/when (condition)
- 비가 오면 집에 있어요 (If it rains, I'll stay home)
-(으)니까 vs -기 때문에
-(으)니까: Conversational, dynamic
- 바쁘니까 못 가요 (I'm busy, so I can't go)
-기 때문에: Formal, explanatory
- 바쁘기 때문에 못 갑니다 (Because I'm busy, I cannot go)
Question Forms
Asking for Reasons
왜 -(으)니까:
- 왜 안 오니까요? (Why aren't you coming?) - Less common
- 왜요? (Why?) - More natural
Rhetorical Questions
- 시간 없으니까 어떻게 해요? (We don't have time, so what should we do?)
- 비싸니까 어디서 사요? (It's expensive, so where can we buy it?)
Special Usage: Discovering Facts
"Oh, so that's why!"
Realizing reasons:
- 아, 여기 병원이니까 조용하네요 (Oh, this is a hospital, so it's quiet)
- 그 사람 유학생이니까 한국어 못 하는구나 (Oh, that person is an exchange student, so they can't speak Korean)
- 오늘 명절이니까 가게가 문 닫았어요 (Oh, it's a holiday, so the stores are closed)
Summary Table
| Verb Type | Stem | -(으)니까 Form | Meaning |
|---|---|---|---|
| Vowel ending | 가다 | 가니까 | since/because go |
| Consonant | 먹다 | 먹으니까 | since/because eat |
| ㄹ irregular | 살다 | 사니까 | since/because live |
| 하다 verb | 공부하다 | 공부하니까 | since/because study |
| Adjective (vowel) | 크다 | 크니까 | since/because big |
| Adjective (consonant) | 좋다 | 좋으니까 | since/because good |
Key Takeaways
- ✅ Strong causation: Emphasizes reason → result
- ✅ Can use with commands: Unlike -아/어서
- ✅ Objective reasons: Based on observable facts
- ✅ Conversational: Common in daily speech
- ✅ Discovery pattern: Realizing causes
- ✅ Formation: -(으)니까 based on final consonant
-(으)니까 is essential for expressing strong causal relationships and is particularly useful when giving commands, making suggestions, or explaining reasons for actions in Korean conversation.