Intermediate / Lesson 19: -(으)니까 (Because/So)
안녕하세요 여러분! A long time ago I made a lesson about this grammar structure, but looking back on that lesson, it seems that it has some inaccuracies and that I just didn’t explain it super well. So I’m redoing it! Especially since this can be a tricky structure in terms of knowing when to use it, I wanted to remake this lesson so hopefully y’all can understand it better :) I hope this is helpful! Let’s start!
-(으)니까 is a structure used to explain a justification or reason for doing something and is translated as “because…” or “…so…” It is similar in meaning to -아/어/여서, but is used in different contexts, which we’ll get to later on in the lesson! Use this formula:
[verb / adjective stem] + (으)니까 = Because [verb / adjective]… / [verb / adjective], so…
Attach -으니까 to stems ending in a consonant
Attach -니까 to stems ending in a vowel
지금은 비가 오고 있으니까 우산을 가져가세요. = It’s raining now, so please bring an umbrella. / Please bring an umbrella because it’s raining right now.
비가 오고 있 + (으)니까 = 비가 오고 있으니까 = Because it’s raining… / It’s raining, so…
신발이 싸니까 살 거예요. = Since the shoes are cheap, I’ll buy them. / I’ll buy the shoes since they’re cheap.
싸 + (으)니까 = 싸니까 = Since it’s cheap… / Because it’s cheap..
Let’s get into the differences between -(으)니까 and -아/어/여서. This, in my opinion, is one of the more difficult concepts to grasp, but I hope my explanations help!
1. Only -(으)니까 can be used for commands and suggestions
One of the differences between -(으)니까 and -아/어/여서 is that -(으)니까 can be used with commands or suggestions, but it’s incorrect to use -아/어/여서 for these things. For example you can say:
지금은 비가 오고 있으니까 우산을 가져가세요.
지금은 비가 오고 있어서 우산을 가져가세요 is WRONG!
This sentence from Talk To Me In Korean is an example of using -(으)니까 for suggestions:
밖에 너무 추우니까 집에 있어봐. = It’s too cold outside, so let’s stay in the house. (informal)
밖에 너무 추워서 집에 있어봐 is WRONG!
2. Only -아/어/여서 can be used for talking about something you are thankful for or sorry about.
If you want to say something like “thank you for the gift” or “sorry I’m late,” you need to use -아/어/여서. For example:
선물을 줘서 감사합니다. = Thank you for the gift.
늦어서 죄송합니다. = Sorry I’m late.
3. -아/어/여서 is used for talking about cause-and-effect relationships, typically about things that happened in the past.
어제는 머리 아파서 학교에 못 갔어요. = I couldn’t go to school yesterday because I was sick.
Here, the cause is that your head hurt, and the effect is that you did not go to school. Your head hurting influenced your absence from school. Notice how this also describes past events.
밖에서 너무 추워서 집에 있었어요. = It was to cold outside, so I stayed at home.
This is another event that happened in the past. The cold temperature outside influenced your staying at home – this is a cause-and-effect situation.
어젯밤에 잠을 못 자서 졸려요. = I couldn’t sleep last night, so I’m sleepy.
The cause of your sleepiness is that you could not sleep last night.
*Important note: Unlike when using -아/어/여서, you can conjugate the stem into the best tense when using -(으)니까. For example, you can say 잠을 못 잤으니까, but you CANNOT say 잠을 못 잤어서. Regardless of when you could not sleep, it would be 잠을 못 자서.
**Another note: You can conjugate stems into the future tense for both though! For example, if you’re using the verb 자다, you can say 잘 거라서 or 잘 거니까. Just attach -ㄹ/을 거 to the stem and then either -라서 or 니까!
4. -(으)니까 is used for talking about a justification or reason for a thought, intention, or action. This is often used for justifying things you are going to do in the future.
엄마가 장미를 좋아하니까 장미를 사려고 해요. = My mom likes roses, so I intend to buy her some.
Your reason for buying your mother roses is that she likes them. Notice that buying roses is something you intend to do in the future.
지난 시험을 떨어졌으니까 다음에는 열심히 공부할 거예요. = I failed the last test, so I’m going to study hard next time.
Your justification for your plans to study hard is that you failed the last test.
You can see this usage of -(으)니까 when talking to others:
마감은 지나갔으니까 가입하면 안 돼요. = The deadline passed, so you cannot join.
학교 근처에 있으니까 담배를 피우면 안 돼요. = You are near a school, so you cannot smoke.
Wow that was a long lesson, but you made it to the end! Even I still struggle to tell when I should use -(으)니까 and when I should use -아/어/여서, so don’t worry if you struggle too! I think with exposure and practice, you will get to know more intuitively when you should use each. As always, if anyone spots any errors in this lesson or have any questions about it, please let me know! Thanks for reading and see you in the next lesson! 다음에 또 봐요!
Join my Discord chat here to practice Korean with others!
Follow me on Instagram here for more Korean content!
Get Drops Premium using my affiliate link to expand your Korean vocab!
Check out my Hilokal to join my live Korean classes for free!
Check out my Ko-Fi to support this blog and my studies! Thank you for your generosity!
