-기 때문에

How to use it

Gives a clear reason or cause; it sounds more formal and emphatic than -아/어서. Past tense can come before it (늦었기 때문에). With nouns: N 때문에 'because of N', N이기 때문에 'because it is N'.

Forming it

Not normally followed by commands or suggestions: ✗ 비가 오기 때문에 우산을 가져가세요 → 비가 오니까 … . ✗ 학생 때문에 할인돼요 (= because of a student) → 학생이기 때문에 할인돼요.

Examples

• 내일 시험이 있기 때문에 오늘은 못 놀아요.

  I have an exam tomorrow, so I can't hang out today.

• 눈 때문에 비행기가 늦게 출발했어요.

  The plane left late because of the snow.

Compared with similar patterns

-아/어서 is the everyday reason connective (no past tense before it); -(으)니까 allows commands and suggestions; -는 바람에 is for an unexpected cause with a bad result.

Related patterns

• -아/어서 because, so (reason); and then (sequence)
• -(으)니까 because, since (reason); when (I did …, I found)
• -는 바람에 because (something unexpected happened) — negative result