Grammar
-(으)니까
because; since
Form
Verb or adjective stem + -(으)니까 — “because”, “since”.
Function
Introduces a reason given as the basis for a conclusion, suggestion, or explanation.
Why this form?
-아/어서 — because; so : often presents a more descriptive cause; -(으)니까 commonly supplies a reason for what follows.
How to build it
After a consonant: -으니까; after a vowel or ㄹ: -니까. With 하다: 하니까. -니까요 can stand as a contextual explanation.
Forms not to confuse
-아/어서
피곤해서 쉬었어요. — I rested because I was tired.
Examples
아픔이 우리를 강하게 만들기도 하니까요. — Because pain can also make us stronger.
추우니까 문을 닫으세요. — It’s cold, so please close the door.