です / だ: The Japanese Copula

Level: N5. (Note: the JLPT publishes no official grammar list; the level shown is the common textbook convention.)

With nouns and na-adjectives, です (desu) and だ (da) — the Japanese copula — often correspond to English “am/is/are”, joining a topic to a noun. (It is not an exact match for every use of “be”.) If you can say 私は学生です (Watashi wa gakusei desu, “I am a student”), you already have the core pattern.

The rule

A copula is a linking word like English “is/am/are”. The everyday copula has two main registers (more formal and literary forms such as である and でございます also exist, and in casual speech the plain だ is often dropped):

• です (desu) — polite. Use it with people you don’t know well, in most learning situations.
• だ (da) — plain. Use it with close friends and in plain-style writing. Sentence-final だ can sound firm, so in relaxed speech it is often dropped: 学生 or 静か instead of 学生だ or 静かだ.

The sentence pattern is topic は noun + copula: 〔topic〕は〔noun〕です.

The particle は (written は but read wa here) marks the topic — see the topic-particle lesson in the Japanese grammar section.

Polite and plain forms

	Plain (だ)	Polite (です)
Present (“is”)	だ (da)	です (desu)
Past (“was”)	だった (datta)	でした (deshita)
Negative (“is not”)	ではない / じゃない (dewa nai / ja nai)	ではありません / じゃありません (dewa arimasen / ja arimasen)
Negative past (“was not”)	ではなかった / じゃなかった	ではありませんでした

じゃ (ja) is the more conversational contraction of では (dewa). The ending sets the politeness: じゃない is plain, じゃありません is polite.

Example sentences

Each sentence was written for this lesson (not copied from a third-party corpus), with readings.

1. 私は学生です。 — Watashi wa gakusei desu. — I am a student.
2. これはペンです。 — Kore wa pen desu. — This is a pen.
3. 彼は先生です。 — Kare wa sensei desu. — He is a teacher.
4. 田中さんは日本人です。 — Tanaka-san wa nihonjin desu. — Tanaka is Japanese. (さん is a gender-neutral honorific attached to names; it has no exact English equivalent)
5. それは私の本です。 — Sore wa watashi no hon desu. — That is my book.
6. 今日は月曜日です。 — Kyō wa getsuyōbi desu. — Today is Monday.
7. 明日は休みです。 — Ashita wa yasumi desu. — Tomorrow is a day off.
8. あれは猫だ。 — Are wa neko da. — That is a cat. (plain)
9. 彼女は学生でした。 — Kanojo wa gakusei deshita. — She was a student. (past)
10. これは水ではありません。 — Kore wa mizu dewa arimasen. — This is not water. (negative)
11. 私は医者ではありません。 — Watashi wa isha dewa arimasen. — I am not a doctor.
12. ここは学校です。 — Koko wa gakkō desu. — This place is a school.

Common mistakes

• ❌ 私は学生だです。 → ✅ 学生です or 学生だ. Use one copula, not both.
• ❌ 忙しいだ。 → ✅ 忙しい / 忙しいです. Don’t put だ after an い-adjective (忙しい = “busy”). After an い-adjective, です only adds politeness.
• ❌ これは水じゃありませんです。 → ✅ これは水ではありません. じゃありません is already the complete polite negative, so don’t add another です. (In conversation you will also hear じゃないです.)
• ❌ (for “was”) 学生です → ✅ 学生でした. Use the past form でした.

Compared with…

• は particle (wa) — marks the topic in front of the copula.
• な-adjectives — these behave like nouns and also take です/だ (静かです = “is quiet”), unlike い-adjectives.

Both are in the Japanese grammar section.

Quick recap before the quiz.

Mini quiz

1. 私は学生＿＿。 (polite “I am a student”)
2. 彼女は学生＿＿。 (polite “she was a student”)
3. これは水＿＿＿＿＿＿。 (polite “this is not water”)
4. True or false: you can say 忙しいだ.
5. あれは猫＿。 (plain “that is a cat”)

Answers

1. です — polite present.
2. でした — polite past.
3. ではありません (or じゃありません) — polite negative.
4. False — い-adjectives don’t take だ; say 忙しい or 忙しいです.
5. だ — plain copula.

Sources & licensing

• Forms cross-checked with Wiktionary (CC BY-SA 4.0); readings checked against Jisho.
• Level placement follows the common JLPT textbook convention (N5).
• Example sentences were written for this lesson (no third-party sentences copied), with romaji readings.

Next

• Back to the Japanese grammar section
• New here? Start with Start Learning Japanese Here