-(으)ㄹ 테니까: Since I Expect / Intend, … | Korean Grammar

-(으)ㄹ 테니까 is the ending you use to lay down a basis for what you're about to ask someone to do: "I'll handle it, so just come," "the roads will be jammed, so let's leave early." It's built from the same bound noun 터 ("expectation, intention") you met in -(으)ㄹ 텐데, but where 텐데 tacks on the contrastive -ㄴ데, this one tacks on the causal -니까 ("because, since"). That single swap flips the whole function: instead of setting up a worry or contrast, -(으)ㄹ 테니까 hands you a reason and then pushes forward into an instruction. The clause that follows is almost always a suggestion, request, or command — that directional pull is the heart of the ending.

The subject decides the meaning

Here is the part that makes -(으)ㄹ 테니까 genuinely tricky: it reads two completely different ways depending on who the subject is.

Subject	Reading	Example
1st person + action verb	intention — "I will…, so…"	내가 낼 테니까 (I'll pay, so…)
2nd/3rd person, or a state / non-volitional verb	prediction — "it'll…, so…"	비가 올 테니까 (it'll rain, so…)

First person → the speaker's intention

When you are the subject and the verb is something you can choose to do, -(으)ㄹ 테니까 states your resolve as the reason for the request that follows. It's the grammar of "leave it to me."

내가 갈 테니까 걱정하지 마.

naega gal tenikka geokjeonghaji ma

I'll go, so don't worry. (casual)

제가 준비할 테니까 오기만 하세요.

jega junbihal tenikka ogiman haseyo

I'll get everything ready, so just come. (polite)

제가 도와드릴 테니까 너무 걱정하지 마세요.

jega dowadeuril tenikka neomu geokjeonghaji maseyo

I'll help you, so please don't worry too much.

Other subject → a prediction

When the subject is someone or something else — or when the predicate is a state you don't control — the very same ending becomes a prediction that grounds your advice.

길이 막힐 테니까 일찍 나가자.

giri makil tenikka iljjik nagaja

The roads will be jammed, so let's leave early.

시험이 어려울 테니까 미리 공부해.

siheomi eoryeoul tenikka miri gongbuhae

The exam's going to be hard, so study ahead. (casual)

벌써 도착했을 테니까 전화해 보세요.

beolsseo dochakaesseul tenikka jeonhwahae boseyo

They've probably arrived by now, so try giving them a call.

Note the past -았/었을 테니까 on that last one: a prediction about something that has presumably already happened ("they'll have arrived by now").

💡

The dividing line isn't just "me vs. not-me" — it's volition. A first-person subject with a verb you can choose (가다, 하다, 내다) gives intention; a first-person subject with a state or non-volitional verb still gives prediction. 저도 바쁠 테니까 ("I'll probably be busy too, so…") is a forecast, not a vow — because 바쁘다 isn't something you decide.

저도 바쁠 테니까 그날은 다른 사람한테 부탁해.

jeodo bappeul tenikka geunareun dareun saramhante butakae

I'll likely be busy too, so ask someone else for that day.

The 터 family: -(으)ㄹ 테니까 vs. -(으)ㄹ 텐데

Because they share the 터 stem, these two get mixed up constantly. Keep them apart by the clause that follows:

-(으)ㄹ 테니까 → the reason for a directive (do this, let's do that, please do this).
-(으)ㄹ 텐데 → a contrast or worry (…but why isn't it? / …you must be, yet…).

내가 도와줄 테니까 걱정 마.

naega dowajul tenikka geokjeong ma

I'll help, so don't worry. (테니까: reason for the command)

If you swapped in 도와줄 텐데, you'd be promising help and then setting up a but ("I'd help you, but…") — a totally different message. When your second clause is an order, a suggestion, or a request, 테니까 is the one you want.

-(으)ㄹ 테니까 vs. plain -(으)니까

Both end in -니까 and both give a reason, but -(으)ㄹ 테니까 carries the extra "I expect / I intend" modality that plain -(으)니까 lacks. Plain -니까 states an observed, current fact; -(으)ㄹ 테니까 projects an expectation into the future.

비가 오니까 우산을 가져가세요.

biga onikka usaneul gajeogaseyo

It's raining, so take an umbrella. (observed fact, right now)

비가 올 테니까 우산을 가져가세요.

biga ol tenikka usaneul gajeogaseyo

It's going to rain, so take an umbrella. (a forecast)

The first speaker is looking at rain out the window; the second is predicting rain that hasn't started. If you mean a forecast, plain 오니까 is wrong — you need the 터.

💡

A self-check for -(으)ㄹ 테니까: read the clause that follows. If it's an order, a suggestion (-자), or a request (-(으)세요), you've used it correctly. If you find a plain statement of fact sitting there instead, the ending is wrong — 테니까 exists to launch a directive, not to close a thought.

Common Mistakes

1. Using it to hedge about yourself. With a first-person subject and an action verb, -(으)ㄹ 테니까 is a firm intention — you can't dilute it with 아마 ("probably"). To genuinely predict about yourself, use 것 같다 or -(으)ㄹ지도 몰라요 instead.

❌ 저도 아마 갈 테니까 같이 가요.

Clashes — 갈 테니까 means 'I intend to go,' so 아마 ('probably') contradicts it.

✅ 저도 갈 테니까 같이 가요.

jeodo gal tenikka gachi gayo

I'm going too, so let's go together.

2. Following it with a flat statement instead of a directive. The 테니까 clause exists to justify a suggestion, request, or command.

❌ 비가 올 테니까 우산이 있어요.

Dangling — a prediction-reason needs an instruction after it, not a bare fact.

✅ 비가 올 테니까 우산을 가져가세요.

biga ol tenikka usaneul gajeogaseyo

It'll rain, so take an umbrella.

3. Using plain -(으)니까 for a future prediction. Present -니까 reports what's happening now; a forecast needs -(으)ㄹ 테니까.

❌ 이따가 길이 막히니까 지금 출발하자.

Off — 막히니까 says the road is jammed now; for 'it'll be jammed' use 막힐 테니까.

✅ 이따가 길이 막힐 테니까 지금 출발하자.

ittaga giri makil tenikka jigeum chulbalhaja

The road will be jammed later, so let's set off now.

4. Confusing it with -(으)ㄹ 텐데. Reason-for-a-command is 테니까; contrast-or-worry is 텐데.

❌ 내가 낼 텐데 넌 그냥 먹어.

Wrong tail — to give a reason for the command, use 테니까.

✅ 내가 낼 테니까 넌 그냥 먹어.

naega nael tenikka neon geunyang meogeo

I'll pay, so just eat.

5. Dropping the 으 on a consonant stem. A consonant-final stem takes -을 테니까.

❌ 제가 다 먹ㄹ 테니까 그냥 두세요.

Wrong — a consonant stem needs -을: 먹을 테니까.

✅ 제가 다 먹을 테니까 그냥 두세요.

jega da meogeul tenikka geunyang duseyo

I'll eat it all, so just leave it.

Key Takeaways

-(으)ㄹ 테니까 = 터 ("expect/intend") + -니까 ("because") — a basis for the directive that follows.
First-person + volitional verb → intention (제가 할 테니까 = "I'll do it, so…"); other subject or a state → prediction (비가 올 테니까 = "it'll rain, so…").
The following clause is almost always a suggestion, request, or command — that's the ending's whole job.
Don't confuse it with -(으)ㄹ 텐데 (contrast/worry) or with plain -(으)니까, which lacks the "I expect/intend" modality.

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