The Korean grammar pattern “-기로 하다” is essential for expressing decisions and promises. It translates to “decide to” or “promise to” in English and is commonly used in daily conversations. In this guide, you’ll learn how to use “-기로 하다” effectively with clear explanations, practical examples, and key tips to avoid mistakes.
Contents
1. Definition
“-기로 하다” is a grammatical structure used to indicate a decision, resolution, or promise. In English, it corresponds to phrases like “decide to” or “promise to.”
2. Form (Structure)
To use ‘-기로 하다’, attach ‘-기로’ to the verb stem and follow it with the verb ‘하다’.
Sentence Structure:
[Verb stem] + -기로 하다 → to decide to do [something]
| Verb Type | Conjugation Example | Meaning |
| 가다 (to go) | 가기로 하다 | to decide to go |
| 공부하다 (to study) | 공부하기로 하다 | to decide to study |
| 먹다 (to eat) | 먹기로 하다 | to decide to eat |
When conjugating, ‘하다’ can be changed to different tenses:
| Tense | Conjugation | Example Sentence |
| Present | -기로 하다 | 내일부터 운동하기로 해요. (I decide to exercise from tomorrow.) |
| Past | 기로 했다 | 우리는 주말에 만나기로 했어요. (We decided to meet on the weekend.) |
| Future | -기로 할 것이다 | 저는 한국에서 살기로 할 거예요. (I will decide to live in Korea.) |
3. Meaning & Usage
1. Expressing Personal Decisions
‘-기로 하다’ is used when talking about a personal choice or decision. These decisions are typically intentional and planned rather than spontaneous.
- 저는 매일 아침 일찍 일어나기로 했어요. (I decided to wake up early every morning.)
- 올해부터 건강을 위해 채식을 하기로 했어요. (I decided to become a vegetarian for my health.)
- 친구와 함께 여행을 가기로 했어요. (I decided to go on a trip with my friend.)
- 내일부터 매일 한국어 공부하기로 했어요. (I decided to study Korean every day starting tomorrow.)
- 부모님께 더 자주 전화하기로 했어요. (I decided to call my parents more often.)
2. Making a Promise or Agreement
‘-기로 하다’ is often used when making a promise or agreement with someone. This usage emphasizes mutual commitments or personal resolutions.
- 우리는 다음 주에 다시 만나기로 했어요. (We promised to meet again next week.)
- 동생과 같이 저녁을 먹기로 했어요. (I promised to have dinner with my younger sibling.)
- 친구와 서로 도와주기로 했어요. (My friend and I promised to help each other.)
- 저는 오늘 저녁에 일찍 자기로 했어요. (I promised myself to sleep early tonight.)
- 우리는 주말마다 운동하기로 했어요. (We agreed to exercise every weekend.)
3. Used in Rules or Fixed Decisions
‘-기로 하다’ can also indicate rules, schedules, or official decisions made by groups or organizations. These decisions are often formal or structured in nature.
- 회사에서는 금요일마다 회의를 하기로 했어요. (The company decided to hold meetings every Friday.)
- 학교에서 모든 학생들이 유니폼을 입기로 했어요. (The school decided that all students must wear uniforms.)
- 우리는 매월 첫째 주 월요일에 회식을 하기로 했어요. (We decided to have a team dinner on the first Monday of every month.)
- 도서관에서는 조용히 하기로 했어요. (It was decided that we must be quiet in the library.)
- 올해부터 재활용을 철저하게 하기로 했어요. (We decided to be strict about recycling this year.)
4. Key Points to Remember
- “-기로 하다” is used for decisions, promises, or resolutions.
- Always attach “-기” after the verb stem.
- Context determines whether it conveys a personal decision or a group agreement.
5. Practice Exercises
Translate the following sentences into Korean using “-기로 하다”:
- I decided to read a book.
→ - We agreed to meet at 7 PM.
→ - She promised to help me tomorrow.
→ - He resolved to exercise every day.
→ - They decided not to eat fast food anymore.
→ - I promised my parents I would study hard.
→ - We decided to visit Jeju Island next month.
→ - She resolved not to use her phone during meals.
→ - He promised his friend he would call him tonight.
→ - We decided not to be late for the meeting.
→
6. Answers
- 책을 읽기로 했어요.
- 우리는 오후 7시에 만나기로 했어요.
- 그녀는 내일 저를 돕기로 약속했어요.
- 그는 매일 운동하기로 결심했어요.
- 그들은 더 이상 패스트푸드를 먹지 않기로 결정했어요.
- 저는 부모님께 열심히 공부하기로 약속했어요.
- 우리는 다음 달에 제주도를 방문하기로 결정했어요.
- 그녀는 식사 중에 휴대폰을 사용하지 않기로 결심했어요.
- 그는 오늘 밤 친구에게 전화하기로 약속했어요.
- 우리는 회의에 늦지 않기로 했어요.
7. Common Mistakes and Tips
⚠️ Mistake 1: Using “-기 위해서” instead of “-기로 하다.”
Incorrect: 공부하기 위해서 결심했어요. ❌
Correct: 공부하기로 결심했어요. ✅
💡 Tip: Use “-기 위해서” for expressing purposes and “-기로 하다” for decisions or promises. These two structures serve different functions in Korean grammar.
⚠️ Mistake 2: Forgetting the particle “-기.”
Incorrect: 운동로 하다. ❌
Correct: 운동하기로 하다. ✅
💡 Tip: Always nominalize the verb with “-기” before attaching “-기로 하다.” Forgetting this step will result in incorrect grammar.
⚠️ Mistake 3: Overusing “-기로 하다” when not expressing decisions or promises.
Incorrect: 나는 매일 학교에 가기로 했어요. ❌ (I decided to go to school every day.)
Correct: 나는 매일 학교에 가요. ✅ (I go to school every day.)
💡 Tip: Use simple present tense for habitual actions instead of “-기로 하다,” which is reserved for expressing decisions or commitments.
“-기로 하다” is an intermediate-level grammar point that plays a vital role in expressing decisions and promises in Korean communication.