“ㄹ/을 텐데,” “ㄹ/을 테니까” Key Differences and Usage in Korean

(2) Verb/Adjective Stem + ㄹ/을 테니(까) (will + so/because + suggestion)

Ends in a batchim -> 을 테니(까)
Ends in a vowel -> ㄹ 테니(까)


This informal expression is commonly used in everyday conversation and has two main functions: (1) providing reasons for suggestions or advice, and (2) expressing strong suppositions or expectations about future actions or situations.


Function 1: Giving Reasons for Suggestions or Advice

One of the primary uses of -(ㄹ)을 테니(까) is to give a reason for making a suggestion, advice, or request. It can imply, “I’ll do (something), so you (do something else),” or “This will happen, so…”

In this context, it can be understood as “since,” “so,” or “because,” and typically appears when the speaker wants to show their intention or expectation and link it to advice or a suggestion for the listener.

When 을 테니까 is used in this role, there are usually 2 people involved in the conversation.
One speaker uses 을 테니까 to explain, “I’ll do this, and you do this.”


Let’s take a look at examples!

제가 여기서 기다릴 테니까, 먼저 가세요.

“I’ll wait here, so you go ahead.”

Here, the speaker is expressing their plan to wait, allowing the other person to leave without worrying.

날씨가 추울 테니까, 따뜻하게 입으세요.

“It’s going to be cold, so dress warmly.”

The speaker is assuming it will be cold and advises the listener to dress accordingly.

오늘은 내가 살 테니까, 다음에는 너가 사!(causally)

“I’ll pay today, so you can pay next time.”

The speaker plans to pay now and uses this as a reason to suggest that the other person can pay next time.

저녁 준비할 테니까, 손님들을 맞아 주세요.

“I’ll get dinner ready, so please greet the guests.”

The speaker is planning to make dinner and asks(advises) the other person to greet the guests in the meantime.





Function 2: Expressing Strong Supposition or Assumption


Another use of -ㄹ/을 테니(까) is to show a strong assumption or expectation about something that will happen. This is similar to saying, “I assume/suppose this will be the case, so…” It allows the speaker to express a confident assumption that the listener can rely on. -> You can use ‘텐데 or 것 같으니까’ here as well!!


Let’s take a look at examples!



지금쯤 도착했을 테니까, 전화해 보세요.

“They’ve probably arrived by now, so give them a call.”

The speaker (strongly) assumes that the person has arrived, suggesting that it’s a good time to contact them.

혼자 가면 힘들 테니까, 내가 같이 가 줄게(casually!).

“It’ll be hard to go alone, so I’ll go with you.”

The speaker expects that going alone will be difficult, offering to accompany the listener.

날씨가 좋을 테니까, 내일 소풍 가요!

“The weather should be nice, so let’s go on a picnic tomorrow!”

The speaker is confident that the weather will be nice and suggests going on a picnic.



When used for function 2, -ㄹ(을) 텐데 / 것 같으니까 can also be used. It conveys more of a tone of self-talk or speculating to oneself. ( 것 같으니까 combines ‘I think‘ with ‘because.'”)



What’s the difference between using 텐데 and 테니까?

Using ‘텐데‘ gives a gentler, more considerate feel. ‘텐데‘ is often used when you’re making a personal observation, a thought or guess to yourself. Since it’s a personal assumption, it feels less direct and more considerate, as if you’re reflecting on the other person’s experience and kindly suggesting they take care of themselves.

On the other hand, ‘테니까‘ gives a slightly more assertive tone. This form can sound more active or intentional, as if you’re stating something based on a reliable expectation rather than just your personal thought.

In summary, ‘텐데’ feels more reflective and thoughtful, often used to make a gentle, considerate suggestion. ‘테니까’ sounds more confident and direct, used when you have a clearer sense of expectation.

✨✨Practice time!! ✨✨

I’ll explain all the possible options, so feel free to use any grammar you think is appropriate,
whether it’s 텐데, 테니까, 것 같으니까, or 것 같아요.



(1) My exams will be over tomorrow, so shall we go watch a movie then?


(2) Everyone’s probably busy, so let’s talk about it later.


(3) It’s likely to rain tomorrow, so bring an umbrella.


(4) It’ll probably be hard, so take breaks as you go.


(5) I’ll handle the food, so you bring the drinks.


(6) I’ll drive this time, so you can drive next time.


(7) There will probably be a lot of people, so it’s best to go early.


(8) It’s probably snowing a lot there right now, so drive carefully.


(9) I’ll make the reservation, so just show up on time.


(10) I’ll keep it quiet, so focus on studying now.

✨Here are the answers !!✨

(1) 내일 시험이 끝날 테니까, 그때 영화 보러 갈래요? (giving a reason for a suggestion, so this is the function 1)

* This is about a fact, something that will definitely happen (not an assumption). In this case, ‘텐데’ is not possible—only ‘테니까’ can be used.



(2) 아마 다들 바쁠 테니까, 나중에 다시 이야기해 보죠. (strong assumption + suggestion, so this is the function 2)

* For personal assumptions, guesses, or opinions, ‘바쁠 텐데‘ or ‘바쁠 것 같으니까/같은데‘ are also possible.




(3) 내일 비가 올 테니(까), 우산을 챙기세요. (strong assumption + suggestion, so this is the function 2)

* For personal assumptions, guesses, or opinions, ‘내일 비가 올 것 같으니까/같은데‘ and ‘비가 올 텐데‘ are also possible




(4) 많이 힘들 테니까/텐데, 조금씩 쉬면서 하세요.
(The speaker assumes the task will be challenging, encouraging the listener to rest, so this is the function 2)

* 많이 힘들 것 같으니까, 많이 힘들 것 같은데 is also possible!

* If you say ‘힘들텐데’ gives it a warmer, more thoughtful tone. ‘텐데’ expresses a personal opinion or guess, almost like you’re talking to yourself, reflecting on how challenging it might be for the other person. It’s not based on a fact but on your own feeling, which makes it feel gentler and more considerate.



(5) 내가 음식 준비할 테니까 너는 음료수를 챙겨 와. (giving a reason for a suggestion, so this is the function 1)

* This is a case of Function 1, so only ‘테니까‘ is possible here. It’s not about personal opinion or assumption; it’s a matter of fact and action. Therefore, using ‘텐데‘ or ‘것 같으니까‘ wouldn’t be appropriate.

* To express ‘to handle,’ you can use ‘맡다,’ which means ‘to be in charge of,’ or simply ‘하다‘ for a more casual tone. For example, you could say: 내가 음식을 할 테니, 너는 음료수를 가져와 (another way to say ‘bring’).

* For something like, ‘I’ll handle people, you handle food,‘ you can say: 내가 사람들 맡을게요. (where ‘handle’ is expressed by ‘맡다‘ meaning ‘to be in charge of’) and 너는 음식 해.“




(6) 제가 이번엔 운전할 테니까, 다음번엔 당신이 운전해요. (Function 1 , giving a reason for a suggestion)
* Since it’s based on an action or fact—not an opinion, assumption, or guess—only ‘테니까‘ can be used here.



(7) 사람들이 많을 테니까 일찍 가는 게 좋겠어.
* For personal assumptions, guesses, or opinions, ‘많을 텐데‘ or ‘많을 것 같으니까/은데‘ are also possible.



(8) 그곳은 지금 눈이 많이 올 테니까 운전 조심해.
* For personal assumptions, guesses, or opinions, ‘올 텐데‘ or ‘올 것 같으니까/은데‘ are also possible.



(9) 내가 예약할 테니까, 제 시간에 오기만 해.
* Since it’s based on an action or fact—not an opinion, assumption, or guess—only ‘테니까’ can be used here.



(10) 조용히 할 테니까 이제 집중해서 공부해.
* Since it’s based on an action or fact—not an opinion, assumption, or guess—only ‘테니까’ can be used here.

Summary

While both 텐데 and 테니까 express assumptions or expectations, 텐데 often carries a hint of speculation or concern about oneself, whereas 테니까 has a more assertive tone. Additionally, 테니까 provides reasons for suggestions or advice, so you can practice distinguishing which one to use accordingly!