What Does Desu Mean in Japanese? です Explained Simply

The short answer

です links a topic to a noun or adjective: がくせいです (I’m a student).
It’s polite. The casual version is だ, or often nothing at all.
Forms: です, じゃないです (isn’t), でした (was), じゃなかったです (wasn’t).
Pronounced like “dess”: the u is barely audible.

What です does

わたしはがくせいですwatashi wa gakusei desu
I am a student.
これはすしですkore wa sushi desu
This is sushi.
きょうはあついですkyō wa atsui desu
It’s hot today.With い-adjectives, です only adds politeness.
げんきですgenki desu
I’m fine.

Grammarians call です a copula: it connects the topic with what it is. With い-adjectives it isn’t grammatically needed, but it makes the sentence polite.

The four forms of です

Form	Polite	Casual	Meaning
present	です	だ	is
negative	じゃないです / ではありません	じゃない	is not
past	でした	だった	was
past negative	じゃなかったです	じゃなかった	was not

がくせいじゃないですgakusei ja nai desu
I’m not a student.
きのうはやすみでしたkinō wa yasumi deshita
Yesterday was a day off.

Common mistakes

Don’t add です to verbs. たべますです is wrong. Verbs have their own polite form: ます.
い-adjective past isn’t でした. あついでした is wrong; say あつかったです. See Japanese adjectives.
Casual だ isn’t always needed. Friends often just say がくせい？ and うん、がくせい. Sometimes だ can even sound blunt or masculine.

Questions with です

がくせいですかgakusei desu ka
Are you a student?
はい、そうですhai, sō desu
Yes, that’s right.
いいえ、ちがいますiie, chigaimasu
No, that’s not right.

“Desu” on the internet

Online, English speakers sometimes add “desu” to sentences as a joke to sound cute or anime-like. In real Japanese it’s simply a polite, everyday word, no cuteness involved.

です with sentence endings

Little particles after です change the tone of the whole sentence:

いいてんきですねii tenki desu ne
Nice weather, isn’t it?ね invites agreement.
これ、おいしいですよkore, oishii desu yo
This is tasty, you know!よ gives new information.
そうですかsō desu ka
Is that so? / I see.
そうですねsō desu ne
That’s right / Let me think.
そうでしょうsō deshō
Right? / I bet.

でしょう: probably

でしょう is the polite probably. You hear it in every weather forecast: あしたはあめでしょう, it will probably rain tomorrow. With a rising tone it asks for agreement: たのしかったでしょう？, that was fun, right?

んです: explaining

You’ll often hear んです instead of plain です after verbs and adjectives: あたまがいたいんです, (the thing is) I have a headache. It adds a nuance of explanation or emphasis and sounds softer and more personal. Learners can understand it early and start using it once the basics sit.

です check0/3

“I’m not a teacher.”
“It was a holiday.”
Casual form of です:

Frequently asked questions

What does desu mean in Japanese?

です (desu) roughly means 'is', 'am' or 'are', linking a topic to a noun or adjective, and it makes the sentence polite: がくせいです means 'I am a student'.

How do you pronounce desu?

It usually sounds like 'dess', because the final u is devoiced (whispered) in natural speech.

What is the casual form of desu?

The plain form is だ (da). In casual conversation it's often dropped entirely.

What does deshou mean?

でしょう means 'probably' and is the polite conjecture form of です, as in weather forecasts: 明日は雨でしょう, 'it will probably rain tomorrow'.