이다
To Be
이다 is the Korean 'to be' verb. It attaches to nouns to say 'Subject is Noun'. For example, '저는 학생이다' means 'I am a student'.
How It Works
이다 is the Korean equivalent of 'to be' (am, is, are). It is always attached directly to the end of a noun, without a space. Its form changes depending on the politeness level and the final sound of the noun it follows.
Standard Polite Form (-요)
This is the most common form in daily conversation.
- After a noun ending in a consonant, use 이에요.
학생 (student) + 이에요 → 학생이에요. (I am a student.)
책 (book) + 이에요 → 책이에요. (It is a book.) - After a noun ending in a vowel, use 예요.
의사 (doctor) + 예요 → 의사예요. (He is a doctor.)
사과 (apple) + 예요 → 사과예요. (It is an apple.)
Formal Polite Form (-ㅂ/습니다)
This form is used in more formal settings, like presentations or news reports. It always becomes 입니다, regardless of the preceding noun.
- 학생 + 입니다 → 학생입니다.
- 의사 + 입니다 → 의사입니다.
Question Forms
To ask a question, you simply raise the intonation at the end of the sentence.
- Polite: 학생이에요? / 의사예요?
- Formal: 학생입니까? / 의사입니까?
Examples (4)
- 저는 학생이에요.
I am a student.
Word by Word: I topic-marker student am.
The noun '학생' ends in a consonant (ㄴ), so '이에요' is used.
- 이것은 사과예요.
This is an apple.
Word by Word: This topic-marker apple is.
The noun '사과' ends in a vowel (ㅘ), so '예요' is used.
- 그 사람은 의사입니까?
Is that person a doctor?
Word by Word: That person topic-marker doctor is (formal question)?
This is the formal question form, '입니까?', used in formal or very polite situations.
- 제 이름은 김민준입니다.
My name is Kim Minjun.
Word by Word: My name topic-marker Kim Minjun is (formal).
This is the formal statement form, '입니다', often used for introductions.
Common Mistakes
Confusing '이에요' and '예요'.
Not Quite이것은 책예요.Better이것은 책이에요.The noun '책' ends in a consonant (ㄱ), so you must use '이에요'. '예요' is only used after nouns that end in a vowel (e.g., '사과예요').
Attaching '이다' to adjectives or verbs.
Not Quite날씨가 예쁘다예요.Better날씨가 예뻐요.'이다' can only be attached to nouns. Adjectives like '예쁘다' (to be pretty) and verbs already contain the meaning of 'to be' and conjugate on their own.
Leaving a space before '이다'.
Not Quite저는 학생 이에요.Better저는 학생이에요.'이다' is a particle-like copula and must be attached directly to the noun without any space.
Learn This First
To understand how 이다 changes form, you need to know basic verb conjugation patterns.
Related Patterns
- 은/는Topic Marker
'이다' sentences identify a topic. The topic marker 은/는 is most commonly used to mark the noun that the '이다' phrase is describing.
- 이/가Subject Marker
The subject marker 이/가 can also be used with '이다', often to identify something for the first time or to add emphasis. For example, '누가 학생이에요?' (Who is the student?).
- -요Politeness Marker
'이다' conjugates to '이에요/예요' in the standard polite speech style. This style is characterized by the -요 ending. Understanding this ending is crucial for using '이다' in everyday conversations.
- -ㅂ/습니다Formal Polite Ending
In formal situations, '이다' conjugates to '입니다'. This uses the formal polite ending, which is important for showing a high level of respect.
- 안/못Not
To say something 'is not' a noun, you do not use the standard negation patterns like '안'. Instead, '이다' has its own special negative form: '아니다' (e.g., 학생이 아니에요 - I am not a student).
Learn Next
Patterns that build on this one.
- -가Busan: Checking a Noun Predicate
- -(으)ㄹ 계획이다Plan to, Intend to
- -(으)ㄹ 뿐이다Only
- -(으)ㄹ 예정이다Be Scheduled to, Plan to
- -는 길이다The Way to, How to
- -는 법이다The Way to, How to
- -는 편이다Tend to, Rather
- -(이)라고Say That (With 이다)
And 8 more in the full list.