-기로 하다
decide to, agree to
Marks the moment a decision is made. Usually reported in the past even when the action is still ahead — because the deciding is what already happened.
Build it
Pick a verb
When to use it
Attach -기로 하다 to any plain stem — no vowel rule, ㄹ stays, and no tense in front. The tense goes on 하다.
The point that surprises learners is that the past form is standard for future plans: 내일 만나기로 했어요 means “we’ve arranged to meet tomorrow.” The meeting is future, but the decision is past, and Korean marks the decision.
It frequently describes a joint arrangement, which is why it fits appointments and agreements so well. 하다 can also be swapped for a more specific verb: 약속하다 (promise), 결정하다 (decide), 정하다 (settle on).
For a resolution about stopping something, the negative goes on the first verb: 담배를 안 피우기로 했어요.
How to attach it
| Situation | Form | Example |
|---|---|---|
| Any verb | -기로 하다 | 가다 → 가기로 하다 |
| Reporting a decision | -기로 했다 | 만나기로 했어요 |
| ㄹ stems keep the ㄹ | -기로 하다 | 만들다 → 만들기로 했어요 |
| Resolving not to | 안 + verb + 기로 | 안 피우기로 했어요 |
| Other verbs | 약속하다, 결정하다 | 가기로 약속했어요 |
| Never takes tense | plain stem only | 갔기로 했어요 is wrong |
In use
내일 세 시에 만나기로 했어요.
We’ve arranged to meet at three tomorrow.
올해부터 담배를 안 피우기로 했어요.
I’ve decided to stop smoking this year.
매일 아침 운동하기로 했어요.
I’ve decided to exercise every morning.
친구하고 같이 여행 가기로 약속했어요.
I promised to travel with a friend.
저녁은 제가 만들기로 했어요.
It’s been decided that I’ll make dinner.
회의는 다음 주로 미루기로 했습니다.
We’ve decided to postpone the meeting to next week.
Compared with
-(으)려고 하다
-(으)려고 하다 is an intention you hold; -기로 하다 is a decision already taken, often with someone else. The second is firmer.
가려고 해요. (I’m thinking of going) / 가기로 했어요. (it’s decided)
-(으)ㄹ 거예요
Both report settled plans, but -기로 했어요 points at the act of deciding, which is why it suits appointments and agreements.
내일 만날 거예요. (I’m meeting them) / 내일 만나기로 했어요. (we’ve arranged to meet)
-(으)ㄹ게요
-(으)ㄹ게요 makes a promise on the spot; -기로 하다 reports a decision already made, possibly some time ago.
제가 할게요. (I’ll do it) / 제가 하기로 했어요. (I’ve been assigned it)
Watch out
내일 세 시에 만나기로 해요.
내일 세 시에 만나기로 했어요.
The decision is already made, so 하다 goes in the past even though the meeting is tomorrow. The present form sounds like you are deciding as you speak.
어제 갔기로 했어요.
어제 가기로 했어요.
-기로 never carries tense. Only 하다 does.
담배를 피우지 않기로 했어요. — and 안 in the same sentence
담배를 안 피우기로 했어요.
Either negation works on its own, but do not stack them. 안 피우기로 했어요 and 피우지 않기로 했어요 are both correct alone.
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