Today we’re going to learn ‘Adjective/Verb-(으)니까, Noun-(이)니까 ‘. (으)니까 and (이)니까 attach after an adjective/verb stem and a noun respectively.
(으)니까 and (이)니까 is a connective ending and it is used to show reason or logical sequences. It expresses the former statement is the cause or reason for the following statement.
We can use 어서/아서 also to show reason but (으)니까 shows more strong reason. Both 어서/아서 and (으)니까) are similar and interchangeable in many cases.
Korean Phrases
To elaborate (으)니까 and (이)니까 let’s look at some examples.
1.
아기를 돌봐야 하니까 공원에 갈 수 없다.
I can not go to the park, because I have to take care of the baby.
돌봐야 하다’ and ‘니까’ are combined and form 돌봐야 하니까.
2.
너무 배고프니까, 음식점으로 가서 밥 먹자. I’m so hungry, so let’s go to the restaurant and eat.
배고프 and’니까 are combined to make 배고프니까.
너무 배고프다. I’m hungry. ( it is a background statement/ situation)
음식점으로 가서 밥 먹자. let’s go to the restaurant and eat. = suggestion.
너무 배고프다 is talking about the reason for the suggestion. And to connect two sentences into one we can use ‘니까’. So, you can say
너무 배고프니까, 음식점으로 가서 밥 먹자. I’m so hungry, so let’s go to the restaurant and eat.
3.
날씨가 추우니까 사우나에 갈까요? Since it’s cold, shall we go to the sauna?
4.
‘날씨가 더우니까 집에서 놀아요.’ Since It’s hot, let’s play at home.
‘더우니까 is the result of combination of the verb ‘덥다’ and ‘니까’.
5.
“밖에 눈이 오니까 시켜 먹을까요?” Since it’s snowing outside, shall we order some food?
Verb ‘오다’ and ‘니까’ are joined to form 오니까.
6.
“그럼 오늘이 설날니까 삼겹살 어때요?” Because today is seollal (Lunar New Year’s Day, New Year’s Day in the lunar calendar), how about samgyupsal?
‘설날니까’ is the combination of the noun ‘설날’ and ‘이니까’.
Now let’s look at the conjugation information of Korean grammar (으)니까 and (이)니까. (으)니까, (이)니까 can be used in both past tense and present tense.
If an adjective/verb stem has the final consonant, ‘으니까’ is used.
웃다 (to laugh) / 묶다 Bind
Remove ‘다’. Then there is the final consonant (ㅅ and ㄲ). So ‘으니까’ is used. So it becomes ‘웃으니까 and Bind 묶으니까 respectively.
Adjective ‘작다 – (to be) small .’
Remove ‘다’. Then there is a final consonant (ㄱ). Then ‘으니까’ is used. So it becomes ‘작으니까.’
When an adjective/ verb stem has no final consonant, ‘니까’ is used.
Verb 이해하다 understand
Remove ‘다’, then there is no final consonant. So, ‘니까’ is used. So it becomes ‘이해하니까.’
Adjective 빠르다: to be fast
Remove ‘다’, then there is no final consonant. So, ‘니까’ is used. So it becomes ‘ 빠르니까.’
Now, let’s look at when an adjective/verb stem ends with the final consonant ‘ㄹ.’
When an adjective/verb stem ends with the ㄹ as a final consonant, delete ‘ㄹ’ and attach ‘니까.’
Verb 울다 (Weep/ to cry)
Remove ‘다.’, then the final consonant is ‘ㄹ’ before ‘다’. Then, delete ‘ㄹ’ and then attach ‘니까.’ So it becomes ‘우니까.’
Verb 알다 (to know)
Remove ‘다.’, then the final consonant is ‘ㄹ’ before ‘다’. Then, delete ‘ㄹ’ and then attach ‘니까.’ So it becomes ‘아니까.’
‘살다 (to live)’
Remove ‘다’, then there is a final consonant ‘ㄹ’ before ‘다’. Then, delete ‘ㄹ’ and then attach ‘니까.’ So it becomes ‘사니까.’
으니까 summary
If an adjective/verb stem has the final consonant, ‘으니까’ is used.
‘먹다’ becomes ‘먹으니까 and 멀다 becomes 멀으니까.’
If an adjective/verb stem does not have the final consonant, ‘니까’ is used.
‘자다’ becomes ‘자니까 and 가다 becomes 가니까.’
If an adjective/verb stem ends with the final consonant ‘ㄹ,’ delete ‘ㄹ’ and attach ‘니까’.
‘만들다’ becomes ‘만드니까 and 건들다 becomes 건드니까.’
이니까 grammar
If the preceding noun has the final consonant, ‘이니까’ is used. For example-
‘학생 (student)’ – (Noun)
(ㅇ) is a final consonant. Then ‘이니까’ is used. So 학생 becomes ‘학생이니까.’
‘선생 (Teacher)’ – (Noun)
(ㅇ) is a final consonant. Then ‘이니까’ is used. So you can say ‘선생이니까.’
토요일 (Saturday) – (Noun)
The last word of 토요일 (Saturday) has the final consonant in the form of (ㄹ). Then ‘이니까’ is used. So 토요일 becomes ‘토요일이니까.’
If the preceding noun does not have the final consonant, ‘니까’ is used.
의사(doctor) / 간호사 (Nurse) – (Noun)
There is no final consonant. Then, ‘니까’ is used. So it becomes ‘의사니까 and 간호사니까.’
가수 (Singer) / 영화표 (movie ticket) – (Noun)
There is no final consonant. Then, ‘니까’ is used. So it becomes ‘영화표니까 and 가수니까.’

았으니까 / 었으니까
았으니까 and 었으니까 are past forms of adjective/verb.
If an adjective/verb stem has ‘ㅏ’ or ‘ㅗ’vowel, ‘았으니까’ is used. For example-
Verb 가다 (to go) / 오다 (to come)
Remove ‘다.’ The vowel before ‘다’ is ‘ㅏand ㅗ’ respectively. Then ‘았으니까’ is used. So it becomes ‘갔으니까 and 왔으니까 respectively.’
Adjective ‘작다 (to be small) / 짧다 (to be short)
Remove ‘다’. The vowel before ‘다’ is ‘ㅏ’. Then ‘았으니까’ is used. So it becomes ‘작았으니까 and 짧았으니까 respectively.’
If an adjective/verb stem’ has vowels other than ‘ㅏ’ or ‘ㅗ’, ‘었으니까’ is used.
만들다 (to make) / 걸다 hang
Remove ‘다.’ The vowel before ‘다’ is ‘ㅡ’and ㅓ. Then ‘었으니까’ is used. So it becomes ‘만들었으니까 and 걸었으니까.’
길다 (to be long) / 합치다 (Combine,unite)
Remove ‘다’. The vowel before ‘다’ is ‘ㅣ’. Then ‘었으니까’ is used. So it becomes ‘길었으니까 and 합치었으니까.’
If an adjective/verb ends in ‘하다’, ‘하다’ changes into ‘했으니까’.
공부하다 (to study) / 적용하다 (apply)
‘했으니까’ is used instead of ‘하다’. So it becomes ‘공부했으니까 and 적용했으니까.’
건강하다 (to be healthy) / 고려하다 (Consider/ take into account)
Remove ‘하다’, and use ‘했으니까.’ So it becomes ‘건강했으니까 and 고려했으니까.’
였으니까/ 이었으니까
였으니까/이었으니까 is the past forms of the noun.
If the preceding noun does not have the final consonant, ‘였으니까/이었으니까’ is used. Let’s look at some examples.
조종사 (pilot)
It has no final consonant. Then, you can use ‘이었으니까.’ So you can say ‘조종사이었으니까.’ 이었 can be shortened to 였. So you can say ‘였으니까.’ ‘조종사였으니까’ is also correct. Both expressions are correct.
If the preceding noun has no final consonant, ‘였으니까’ is more commonly used. So ‘조종사였으니까’
If the preceding noun has the final consonant, ‘이었으니까’ is used.
사장 (Boss)
It has final consonant. Then you can use ‘이었으니까’. So you can say ‘사장이었으니까.’ But, you cannot abbreviate ‘이었’ to ‘였’. When the preceding noun has final consonant, then you can use ‘이었으니까’ only. So ‘사장이었으니까’ is correct.
(으)니까, (이)니까 Examples
Let’s see some more examples in the present form. Sentences are made by using (으)니까, (이)니까.’
‘수업 곧 시작하니까 핸드폰을 꺼 주세요.’ Because the class starts soon, turn off your mobile phone.
Verb ‘시작하다’ and ‘니까’ are combined and 시작하니까 is made.
‘오늘은 주말이니까 좀 쉬어요’ Because it’s holiday, take a break.
‘주말이니까’ is a combination of the noun ‘주말’ and ‘이니까.’
‘시간이 있으니까 버스를 탑시다.’ Because we do have time, let’s take a bus.
있으니까 is the result of combination of 있다 and 으니까.
았/었/했으니까 Example
Now let’s see the past form. Let’s make a sentence using ”았/었/했으니까, ‘이었/였으니까.’
‘운동을 열심히 했으니까 살을 뺄거예요.’ Because you’ve worked hard, you will lose weight. 했으니까 is the result of a combination of ‘하다’ + 으니까.’
’63 빌딩은 갔으니까 다른데 가요.’ Because I’ve been to 63 buildings, let’s go to another place. ‘갔으니까’ is the result of combination of the verb ‘가다’ and ‘았으니까’.
‘어제가 많이 쉬었으니까 오늘은 열심히 합시다. Let’s work hard today because yesterday was a free day.
쉬었으니까 is the result of combination of the verb 쉬다 and 았으니까.
날씨가 추우니까 사우나로 갈까요?
춥다’ has a ‘ㅂ’ irregular adjective. So ‘ㅂ’ changes into ‘우’ now add ‘니까’ to make 추우니까.