TL;DR
- -아/어/여서 means "because" or "so" and connects two clauses where the first explains the reason for the second
- Attach it directly to verb/adjective stems: if the stem's final vowel is ㅏ or ㅗ use -아서, otherwise use -어서 (하다 verbs become 해서)
- Unlike -니까, you can't use commands/suggestions in the second clause, and -아/어/여서 feels more natural and conversational 💬
What does -아/어/여서 mean?
-아/어/여서 is one of the most common ways to say "because" or "so" in Korean. It connects two clauses where the first clause gives the reason for what happens in the second clause.
Think of it like: [Reason] -아/어/여서 [Result]
How to form it
Take the verb or adjective stem and add the right ending:
If the stem's final vowel is ㅏ or ㅗ → use -아서
→ 배고파서 라면 먹었어요 (I was hungry so I ate ramen)
→ 날씨가 좋아서 산책했어요 (The weather was nice so I went for a walk)
If the stem's final vowel is anything else → use -어서
→ 피곤해서 일찍 잤어요 (I was tired so I slept early)
→ 재미있어서 두 번 봤어요 (It was fun so I watched it twice)
For 하다 verbs → becomes 해서
→ 공부해서 시험 잘 봤어요 (I studied so I did well on the test)
→ 청소해서 방이 깨끗해요 (I cleaned so the room is clean)
When to use it
Use -아/어/여서 when:
- You're explaining why something happened or why you did something
- The reason directly leads to the result
- You want a natural, conversational tone
→ 시간이 없어서 택시 탔어요 (I didn't have time so I took a taxi)
→ 비가 와서 집에 있었어요 (It was raining so I stayed home)
→ 머리가 아파서 약 먹었어요 (My head hurt so I took medicine)
Important restrictions ⚠️
You cannot use commands, requests, or suggestions in the second clause with -아/어/여서.
❌ 배고파서 밥 먹으세요
✅ 배고프니까 밥 먹으세요 (Since you're hungry, eat)
❌ 시간이 없어서 빨리 가자
✅ 시간이 없으니까 빨리 가자 (We don't have time so let's go quickly)
For commands and suggestions, use -니까 instead!
-아/어/여서 vs -니까
Both mean "because," but they're used differently:
-아/어/여서:
- More natural and conversational
- Reason and result feel connected as one flow
- Can't use with commands/suggestions
-니까:
- More formal or emphatic
- Can use with commands/suggestions
- Sometimes implies the speaker just realized the reason
→ 추워서 창문 닫았어요 (It was cold so I closed the window) - natural flow
→ 추우니까 창문 닫으세요 (It's cold so please close the window) - command
More examples 🌟
→ 친구를 만나서 기뻤어요 (I met my friend so I was happy)
→ 커피를 마셔서 잠이 안 와요 (I drank coffee so I can't sleep)
→ 한국어를 배워서 드라마를 봐요 (I'm learning Korean so I watch dramas)
→ 늦어서 미안해요 (I'm late so I'm sorry / Sorry for being late)
→ 돈이 없어서 못 사요 (I don't have money so I can't buy it)
Exceptions
Sequential actions vs reasons:
Sometimes -아/어/여서 describes a sequence of actions rather than a cause-and-effect relationship. Context tells you which meaning is intended!
→ 집에 가서 쉬었어요 (I went home and rested) - sequence
→ 피곤해서 쉬었어요 (I was tired so I rested) - reason
With 있다/없다:
→ 시간이 있어서 영화 봤어요 (I had time so I watched a movie)
→ 돈이 없어서 못 갔어요 (I didn't have money so I couldn't go)
These work naturally with -아/어/여서! 👍
Try the following exercise.
Fill in the blanks using -아/어/여서 to connect the two clauses. 📝
- 배가 _ 밥을 먹었어요.
Answer
고파서
- 날씨가 _ 집에 있었어요.
Answer
추워서
- 머리가 _ 약을 먹었어요.
Answer
아파서
- 피곤_ 일찍 잤어요.
Answer
해서
- 시간이 _ 택시를 탔어요.
Answer
없어서
- 친구가 _ 같이 영화를 봤어요.
Answer
와서
- 돈이 _ 못 샀어요.
Answer
없어서
- 재미_ 두 번 봤어요.
Answer
있어서
- 비가 _ 우산을 가져갔어요.
Answer
와서
- 한국어를 _ 한국에 갔어요.
Answer
배워서
Vocabulary
배가 고프다 - to be hungry
날씨 - weather
춥다 - to be cold
머리가 아프다 - to have a headache
약 - medicine
피곤하다 - to be tired
일찍 - early
자다 - to sleep
시간 - time
없다 - to not have/exist
택시를 타다 - to take a taxi
친구 - friend
오다 - to come
영화를 보다 - to watch a movie
돈 - money
사다 - to buy
재미있다 - to be fun/interesting
비 - rain
우산 - umbrella
가져가다 - to take/bring
배우다 - to learn
Common mistakes ⚠️
- 🚫 Don't use -아/어/여서 when giving commands or suggestions — use -니까 instead
- 🚫 Remember to use -해서 (not -하여서) for 하다 verbs in casual speech
- 🚫 Avoid using -아/어/여서 in future tense sentences — the second clause should describe what happened as a result
- 🚫 Don't forget vowel harmony: ㅏ/ㅗ → -아서, all other vowels → -어서, 하다 → -여서
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