Verb To Be 이다 in Korean

Unlike English, Korean makes no distinction for the choice of verb to be (am, are, is) between first-person, second-person and third-person subjects. Only a single verb to be 이다 is used.

We only attach 이다 (or its modified forms) to nouns and noun phrases. Korean adjectives are verb-like and do not require 이다 for sentence construction.

Summary for Korean Verb To Be 이다 (Present, Past, Present Negative)

Speech Level Plain Form Formal Polite Informal Polite Formal Casual Informal Casual
is, am, are 이다 입니다 이에요/예요 인다 이야/야
was, were 이었다 이었습니다 이었어요 이었다 이었어
is not, am not, are not 아니다 아닙니다 아니에요 아닌다 아니야

Recall that the subject of a sentence can be omitted (if it is understood by the context), and verb is always at the end of a Korean sentence.


The Korean sentences above with different speech levels convey the same meanings. Notice that (book) is a noun in the sentences.

The choice of 이에요/예요 and 이야/야 is based on Consonant-Vowel Sequences in Spoken Korean.

  • If the noun ends with a vowel, use 예요 or 야.
  • If the noun ends with a consonant, use 이에요 or 이야.

Related Grammar Points