This expression is a combination of -(으)ㄹ 터이다, which expresses the speaker's supposition or intention, and (으)니까, which expresses a reason.

In a sentence with this construction, the second clause contains the speaker's suggestion or statement of advice to the listener while the first clause provides the speaker's reason for giving such a suggestion or advice.

Details

1. This expression can also be used at the end of a sentence in the form of -(으)ㄹ 테니까요.

일찍 출발하세요, 월요일이라 길이 막힐 테니까요.

Leave early. There will be a traffic jam since it's Monday.

2. Expressions such as 걱정이다, 고맙다 and 미안하다 cannot follow -(으)ㄹ 테니까

바쁘실 테니까 참석해 주셔서 감사합니다. ✕

피곤할 테니까 일찍 나오라고 해서 미안해요. ✕

3. This expression is a combination of -(으)ㄹ 터이다, which states an intention, and (으)니까，and is also used to state the speaker's will or intention. As such, it can only be used when the subject is in the first person. The expression is then followed by the speaker's suggestion or request to the listener to do something. Additionally, only verbs can come before -(으)ㄹ 테니까 and they cannot be in the past tense.

가: 재영 씨, 앞으로 어떻게 연락하면 될까요?

Jaeyeong, how should I contact you from now on?

나: 제 이메일 주소를 가르쳐 드릴 테니까 여기로 연락 주세요.

I'll give you my email address, so you can contact me that way.

가: 손님이 오시니까 빨리 집을 정리해야겠어요.

I've got to clean up the house fast because some guests are coming.

나: 제가 거실을 정리할 테니까 당신은 방 청소 좀 해 줄래요?

111 clean up the living room, so will you clean the other rooms?

Although (으)ㄹ 텐데 and -(으)ㄹ 테니까 are used to express supposition, they differ the following respects.

Kimchi Reader

The second part of the sentence gives the speaker's advice or suggestion to the listener. The first part explains why the speaker is giving that advice or suggestion. '까' is sometimes omitted.

Details

Other usages

It can also be used at the end of a sentence in the form of (으)ㄹ 테니까요.