-고 해서 Grammar in Korean: Meaning and How to Use It

What you'll learn

• Attach -고 해서 to verbs, adjectives and 이다, with no change to any stem.
• Use 도 in the first clause to show that there are other reasons.
• Put the past inside the first clause when you need it.
• Tell -고 해서 apart from -아/어서 and -(으)니까.

Prerequisites: the linking ending -고 and the lesson on -아/어서. Time: about 15 minutes.

Key facts

• -고 해서 means "among other reasons." The reason is one of several, so the tone is soft.
• Form: stem + -고 해서. No stem changes, because -고 begins with a consonant.
• The past goes in the first clause: 피곤했고 해서. Nouns take 이고 해서.
• 도 in the first clause ("also") often signals that more reasons exist.
• The result can be a statement, a suggestion or a promise.

Listen to two model sentences.

The next section defines the pattern.

What Does -고 해서 Grammar Mean?

-고 해서 joins two ideas. -고 means "and," and 해서 is the verb 하다 ("do") in the -아/어서 form, so you can read the whole phrase as "and, doing so." The speaker lists one reason with 고 and then leaves the door open for others. The meaning is "for reasons like this one, and some others."

Three ideas follow.

• The reason is one of several. The listener understands that there may be more.
• The tone is soft and modest. You are not claiming that this is the only cause.
• The result is whatever you did or decided. It often sounds casual and friendly.

Two sound notes help. In 좋고, the ㅎ and ㄱ meet and become an aspirated [ㅋ], so the word is said [조코], and RR writes joko in a predicate. In 산책했어요, the ㄱ of 책 and the ㅎ of 했 meet, and the word is said [산채캐써요], written sanchaekaesseoyo. The next section shows how to form the pattern.

How Do You Form -고 해서?

Attach -고 해서 to the stem, which is the dictionary form without 다. The ending begins with a consonant, so every stem works in the same way.

Stems Ending in a Vowel

Add 고 해서 directly.

The sentence 비도 오고 해서 집에서 쉬었어요 means "It was raining too, so I rested at home." The sentence 배도 고프고 해서 라면을 끓였어요 means "I was hungry too, so I boiled instant noodles."

Stems Ending in a Consonant

The ending does not change. There is no 으, because -고 does not need it.

Spoken, 없고 is [업꼬] because the ㅂ before ㄱ tenses the ㄱ. The word 좋고 is [조코]. The sentence 시간도 없고 해서 택시를 탔어요 ("I had no time either, so I took a taxi") is said [시간도 업꼬 해서 택씨를 타써요.].

Irregular Stems and Nouns

• No stem changes. ㄹ stems keep ㄹ (길고 해서), ㅂ stems keep ㅂ (춥고 해서), ㄷ stems keep ㄷ (듣고 해서), and 르 stems keep 르 (모르고 해서). The reason is that the ending begins with a consonant, so none of the usual changes apply.
• Nouns take 이다, so the form is 이고: 주말이고 해서, 학생이고 해서, 휴일이고 해서. After a vowel it is also 이고.
• Past tense puts 았/었 inside the first clause: 피곤했고 해서, 늦었고 해서.
• Honorific puts 시 inside: 바쁘시고 해서.

The next section builds a full sentence.

Worked Example: Building 날씨도 좋고 해서 산책했어요

Say that you took a walk because the weather was nice, and maybe for other reasons too. Follow five steps.

1. Write the first reason. "The weather is good" is 날씨가 좋다. Swap 가 for 도 ("also"): 날씨도 좋다. This hints that there are other reasons.
2. Remove 다. The stem is 좋.
3. Add 고 해서. 좋 + 고 해서 = 좋고 해서. Keep the space before 해서.
4. Write the result. "I took a walk" is 산책했어요.
5. Join the parts. 날씨도 좋고 해서 산책했어요.

You'll know it worked when the first clause ends in -고, a space and 해서 follow, and the sentence sounds like you are giving one of your reasons, not the whole case. If you want to give only one firm reason, use 날씨가 좋아서 산책했어요 instead.

The next section covers tense and sentence types.

Which Tenses and Sentence Types Work with -고 해서?

The first clause can carry past tense, and the last verb carries the speech level.

Most sentences end in a statement about something you did. Unlike -아/어서, the pattern also fits a promise or a suggestion, because the speaker is giving a personal reason, much like -(으)니까. 오늘은 월급날이고 해서 제가 살게요 means "It's payday, so I'll treat you," and 비도 오고 해서 오늘은 집에서 쉬자 means "It's raining too, so let's rest at home."

The past tense goes inside the first clause when the reason itself belongs to the past: 피곤했고 해서 일찍 잤어요.

Spoken, the ending -ㄹ게요 of a promise is tensed: 살게요 is [살께요] and 쉴게요 is [쉴께요]. RR does not show this tensing, so it reads salgeyo and swilgeyo.

The next section compares -고 해서 with -아/어서 and -(으)니까.

How Is -고 해서 Different from -아/어서?

All three give a reason. The difference is how many reasons the speaker implies and what can follow.

Compare these.

• 피곤하고 해서 일찍 잤어요. "I was tired and so on, so I went to bed early." The speaker implies that tiredness was not the only reason.
• 피곤해서 일찍 잤어요. "I was tired, so I went to bed early." Tiredness is the reason.
• 피곤하니까 일찍 주무세요. "You're tired, so please sleep early." A reason leading to a request.

If you want to sound firm, use -아/어서. If you want to sound modest or to leave room for other reasons, use -고 해서. If you want to follow with a command, -(으)니까 is the safest.

The next section covers common uses and edge cases.

Variations and Edge Cases of -고 해서

Listing More than One Reason

You can list several reasons with -고 -고 해서: 날씨도 좋고 기분도 좋고 해서 산책했어요 ("The weather was nice, and my mood was good too, so I took a walk"). Each 고 adds a reason, and 해서 closes the list.

The Answer Fragment

When someone asks why, you can answer with the reason alone: 왜 일찍 왔어요? 일도 끝나고 해서요. ("Why did you come early?" "My work was finished too, so."). The polite 요 comes after 해서 and gives [해서요]. This is a gentle way to say "among other things."

Polite Exits and Refusals

-고 해서 is useful when you leave or decline. 시간도 늦었고 해서 이만 가 볼게요 means "It's getting late too, so I'll be going now." 몸도 안 좋고 해서 오늘은 쉴게요 means "I'm not feeling well too, so I'll rest today." The wording is soft, and you do not have to give your full reason.

도 as a Signal

The particle 도 in the first clause is not required, but it often appears. It says "also," which matches the idea of "among other reasons." Without it, the sentence still works.

A Reason That Is the Whole Story

If one reason is the only cause, -고 해서 can sound a little off. 아파서 병원에 갔어요 is the natural way to say that you went to the hospital because you were sick. The sentence 아프고 해서 병원에 갔어요 suggests that illness was only one of several reasons.

The next section lists the mistakes that appear most often.

What Mistakes Do Learners Make with -고 해서?

Learners make six predictable mistakes. Each has a reason and a fix.

Learners often leave out 해서. Without it, 날씨도 좋고 산책했어요 is just a list: "The weather was nice, and I took a walk." It does not say the weather was a reason. Fix: add 해서 to make the cause clear.

Learners often put the polite ending before 해서. Wrong: 좋아요 해서. Right: 좋고 해서. Fix: attach 고 to the bare stem, with no ending in between.

Learners often put a tense on 해서. Wrong: 날씨도 좋고 했어서 산책했어요. Right: 날씨도 좋고 해서 산책했어요. Fix: 해서 never changes. Put the past on the first verb (피곤했고 해서).

Learners often use it for one major reason. It sounds odd: 아프고 해서 병원에 갔어요. Better: 아파서 병원에 갔어요. Fix: use -아/어서 when one reason is the whole story.

Learners often confuse it with -고 나서. The pattern -고 나서 means "after doing" (밥을 먹고 나서 갔어요). Fix: -고 해서 gives a reason, and -고 나서 gives order in time.

Learners often join 고 and 해서 into one word. Wrong: 좋고해서. Right: 좋고 해서. Fix: 해서 is a separate word (a form of 하다), so standard spelling puts a space before it.

The next section gives you practice.

Practice and Answers

Do the four tasks, then compare with the key.

Task 1: add the ending. Write the form with -고 해서.

1. 오다
2. 없다
3. 춥다
4. 늦다 (past)
5. 주말 (noun)

Task 2: fix the error. Each sentence has one mistake. Rewrite it correctly.

1. 날씨도 좋아요 해서 산책했어요.
2. 날씨도 좋고 했어서 산책했어요.
3. 날씨도 좋고 산책했어요. (you want to say it was a reason)

Task 3: translate. Write in Korean: "I was tired and so on, so I went to bed early." and "It's getting late, so I'll be going now."

Task 4: write your own. Write one sentence that gives one reason among several for something you did today, and one polite sentence that declines an invitation.

Answer key

1. (1) 오고 해서 (2) 없고 해서 (3) 춥고 해서 (4) 늦었고 해서 (5) 주말이고 해서
2. (1) 날씨도 좋고 해서 산책했어요. (2) 날씨도 좋고 해서 산책했어요. (3) 날씨도 좋고 해서 산책했어요.
3. 피곤하고 해서 일찍 잤어요. 시간도 늦었고 해서 이만 가 볼게요. Other correct versions exist.
4. Sample answers: 비도 오고 해서 집에서 공부했어요. 몸도 안 좋고 해서 이번에는 못 갈 것 같아요. Any pair is correct if the reason is a bare stem plus 고, a space and 해서 follow, and the result makes sense.

If task 1 was correct, you have the form rule. If task 2 was hard, review where 해서 stands in the sentence. The next section points you to what comes after this lesson.

What Should You Learn after -고 해서 Grammar?

After -고 해서, review -아/어서, the main-reason pattern, and -(으)니까, the reason that leads to a command.

For a wider view, the parent page Cause and Reason lists every pattern in this group. -고 해서 sits at level B2 on the Advanced Grammar list, which is an editorial estimate. For the tense that goes inside the first clause, see past tense -았/었-. TOPIK is run by the National Institute for International Education (NIIED); check topik.go.kr for what the exam covers.

This lesson covers -고 해서 in everyday Korean. It does not cover every spoken shortening. About this page. Last updated 2026-10-09. Revised Romanization follows the national rules and is shown only as a learning aid.

Frequently Asked Questions

What Does -고 해서 Mean?

-고 해서 means "among other reasons" or "partly because". It gives one reason and leaves room for others, which makes the sentence sound soft and modest. 날씨도 좋고 해서 산책했어요 means "The weather was nice too, so I took a walk." It is not a claim that the weather was the only cause.

How Do I Attach -고 해서 to a Verb or Adjective?

Remove 다 from the dictionary form and add -고 해서. Nothing changes, because -고 begins with a consonant: 오고 해서, 없고 해서, 길고 해서, 춥고 해서. Nouns take 이고: 주말이고 해서. Keep a space before 해서. The particle 도 on the first subject is common but not required.

Can -고 해서 Be Used in the past Tense?

Yes. Put 았/었 inside the first clause when the reason itself is in the past: 피곤했고 해서 일찍 잤어요. The word 해서 never changes, so do not write 했어서. The last verb carries the tense of the result, such as 잤어요. A future reason can use -(으)ㄹ 것 같고 해서.

Is -고 해서 Used in Speech or Only in Writing?

It is mainly spoken and informal. People use it to give friendly, modest reasons and to leave or decline politely, as in 시간도 늦었고 해서 이만 가 볼게요. It also appears in casual writing such as messages. In formal reports and notices, other connectors such as -(으)므로 or -기 때문에 are more usual.

What Is the Most Common Mistake with -고 해서?

The most common mistake is leaving out 해서, as in 날씨도 좋고 산책했어요, which only lists two facts and does not say that one is a reason. Another is using -고 해서 for the one and only reason: 아프고 해서 병원에 갔어요 sounds odd. Use -아/어서 there.

What Is the Difference between -고 해서 and -아/어서?

-아/어서 gives the main reason in a neutral tone, and it cannot be followed by a command or a suggestion. -고 해서 gives one reason among several, in a softer tone, and it can lead into a promise or suggestion. 피곤해서 일찍 잤어요 says tiredness was the reason; 피곤하고 해서 일찍 잤어요 says tiredness was one of them.

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