Decision/ Planning/ Promise -기로 하다

Keyword #
약속, 결심, 계획
Lesson #
Section
Intermediate Grammar

TL;DR

  • -기로 하다 is used to express decisions, plans, or promises that you or someone else has made 📋
  • Attach -기로 하다 to the verb stem (e.g., 가다 → 가기로 하다) to mean "decide to [verb]" or "plan to [verb]" 🎯
  • Use -기로 했다 (past tense) when talking about decisions already made, and -기로 할 거예요 (future) for decisions you're about to make ⏰

What is -기로 하다? 🤔

-기로 하다 is your go-to grammar pattern when you want to talk about decisions, plans, or promises! 💪
It literally means "decide to do something" or "plan to do something" ✨
This pattern shows that a choice has been made (or will be made) about a future action 🔮

How to Form It 🔧

The structure is super simple! 🎉
Verb stem + -기로 하다
Let's see some examples:
→ 가다 (to go) → 가기로 하다 (decide to go)
→ 먹다 (to eat) → 먹기로 하다 (decide to eat)
→ 공부하다 (to study) → 공부하기로 하다 (decide to study)
→ 만나다 (to meet) → 만나기로 하다 (decide to meet)
Easy, right? 😊 No irregular forms to worry about here! 🙌

When to Use It 📅

Use -기로 하다 in these situations:
1. Personal decisions you've made 💭
→ 내일 운동하기로 했어요. (I decided to exercise tomorrow.)
→ 담배를 끊기로 했어요. (I decided to quit smoking.)
2. Plans or agreements with others 🤝
→ 친구랑 영화 보기로 했어요. (I made plans to watch a movie with my friend.)
→ 우리 6시에 만나기로 했어요. (We decided to meet at 6 o'clock.)
3. Promises 🤞
→ 매일 한국어 공부하기로 했어요. (I promised to study Korean every day.)
→ 비밀로 하기로 했어요. (We agreed to keep it a secret.)

Tense Variations ⏰

You can change the tense of 하다 to show when the decision was made! 🕐
Past tense: -기로 했다 (decided)
→ 한국에 가기로 했어요. (I decided to go to Korea.)
Present/Future tense: -기로 하다 (will decide / deciding)
→ 내일 결정하기로 해요. (I'll decide tomorrow.)
Future intention: -기로 할 거예요 (will decide)
→ 다음 주에 결정하기로 할 거예요. (I will decide next week.)
The most common form you'll hear? -기로 했어요! 🎯

Common Examples in Real Life 🌟

Here are some phrases you'll hear all the time! 🗣️
→ 저녁에 치킨 먹기로 했어요. (We decided to eat chicken for dinner.)
→ 이번 주말에 등산하기로 했어요. (We decided to go hiking this weekend.)
→ 한국어로만 말하기로 했어요. (I decided to speak only in Korean.)
→ 다이어트 하기로 했어요. (I decided to go on a diet.)
→ 매일 일찍 일어나기로 했어요. (I decided to wake up early every day.)

Exceptions ⚠️

There are no major exceptions for this grammar pattern! 🎊
The formation is consistent across all verbs - just attach -기로 하다 to any verb stem 💯
One small note though: When the decision was mutual or involves a group, context makes it clear who decided what 👥
→ 같이 공부하기로 했어요. (We decided to study together.)
In this case, "we" is understood from context and the word 같이 (together) 🤗
 
Try the following exercise.
Fill in the blanks using '-기로 하다' to express decisions, plans, or promises. 📝
 
  • 저는 내년에 한국어 시험을 보 .
    • Answer
    기로 했어요
 
 
  • 우리는 주말마다 운동하 .
    • Answer
    기로 했어요
 
 
  • 친구와 다음 달에 여행 가 .
    • Answer
    기로 했어요
 
 
  • 회사에서 새로운 프로젝트를 시작하 .
    • Answer
    기로 했습니다
 
 
  • 나는 담배를 끊 .
    • Answer
    기로 했어요
 
 
  • 부모님께 매일 전화 드리 .
    • Answer
    기로 했어요
 
 
  • 우리 팀은 매주 회의를 하 .
    • Answer
    기로 했어요
 
 
  • 오늘부터 일찍 자고 일찍 일어나 .
    • Answer
    기로 했어요
 
 
  • 그 친구와 다시는 싸우지 않 .
    • Answer
    기로 했어요
 
 
  • 학생들은 숙제를 매일 하 .
    • Answer
    기로 했어요
Vocabulary
시험 - exam, test
보다 - to take (a test)
운동하다 - to exercise
여행 가다 - to go on a trip
프로젝트 - project
시작하다 - to start
담배 - cigarette
끊다 - to quit
전화 드리다 - to call (honorific)
회의 - meeting
일찍 - early
자다 - to sleep
일어나다 - to wake up
싸우다 - to fight
숙제 - homework
Common mistakes
  • ⚠️ Don't forget to change the verb to its noun form before adding '-로 하다' (e.g., 가다 → 가기로 하다, not 가로 하다)
  • 🔄 Remember that '기로 하다' is used for decisions already made, not for spontaneous actions happening right now
  • ⏰ Past tense '기로 했다' is most common because decisions are usually made before the speaking moment
  • ❌ Don't confuse '-기로 하다' (decision) with '-ㄹ 거예요' (simple future plan) — the first emphasizes the act of deciding