だ

だ
auxiliary
is, am, are (plain copula)
informalgrammatical
1. is, am, are (plain copula)
The plain/casual form of the copula, used to link a subject to a predicate noun or na-adjective. This is the informal equivalent of です.
私(わたし)は学生(がくせい)だ。
I am a student.
今日(きょう)は日曜日(にちようび)だ。
Today is Sunday.
彼(かれ)は先生(せんせい)だ。
He is a teacher.

だ is the plain copula in Japanese, used in casual speech and writing.

Forms

Polite equivalent

  • です (polite present)
  • でした (polite past)

Usage

  • Used at the end of sentences in casual/plain speech
  • Follows nouns and な-adjectives
  • With い-adjectives: だ is NOT used (say 高(たか)い, not ×高(たか)いだ)
  • Often omitted in casual speech, especially by women and in questions

Related Words

Related: です (polite copula)
general
Added 2026.2.2 19:21 · Revised 2026.9.2 13:01
09000/09496_da