Learn How to Conjugate the Japanese Verb "Suru"

The Common Irregular Verb for "to Do"

Woman looking into the distance
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One of the most common irregular verbs used in the Japanese language is "suru", which, when translated into English, means "to do." 

Conjugation Table

Conjugation of the irregular Japanese verb "suru" into present tense, past tense, conditional, imperative, and more:

suru (to do)

Informal Present
(Dictionary Form)
suru
する
Formal Present
(~ masu Form)
shimasu
します
Informal Past
(~ ta Form)
shita
した
Formal Past shimashita
しました
Informal Negative
(~ nai Form)
shinai
しない
Formal Negative shimasen
しません
Informal Past Negative shinakatta
しなかった
Formal Past Negative shimasen deshita
しませんでした
~ te Form shite
して
Conditional sureba
すれば
Volitional shiyou
しよう
Passive sareru
される
Causative saseru
させる
Potential dekiru
できる
Imperative
(Command)
shiro
しろ

Sentence Examples

A few sentence examples using "suru": 

Shukudai o shimashita ka.
宿題をしましたか。
Did you do your homework?
Asu made ni shite kudasai.
明日までにしてください。
Please do it by tomorrow.
Sonna koto dekinai!
そんなことできない!
I can't do such a thing!

To Complete an Action

The verb "suru" has many commonly-used applications. While it means "to do" on its own, with the addition of an adjective or depending upon the situation, it can take on a number of different meanings from describing the senses to making a decision to accompanying loan words. 

Suru is used in phrases conveying execution of an action. The phrase structure: adverb form of I-adjective + suru . 

To change I-adjective to adverb form, replace the final ~i with ~ku. (e.g. ookii ---> ookiku)

A sentence example of "suru" used to convey a completed action: 

Terebi no oto o ookiku shita.
テレビの音を大きくした。

I turned up the volume of the TV.

Adverb form of Na-adjective + suru
To change Na-adjective to adverb form, replace the final ~na with ~ni:(e.g. kireina ---> kireini):

Heya o kireini suru.
部屋をきれいにする。

I'm cleaning the room.

To Decide

"Suru" can be used to exemplify making a decision from several different options: 

Koohii ni shimasu.
コーヒーにします。
I'll have coffee.
Kono tokei ni shimasu.
この時計にします。
I'll take this watch.

To Price

When accompanied by phrases indicating prices, it means "cost":

Kono kaban wa gosen en shimashita.
このかばんは五千円しました。

This bag cost 5,000 yen.

The Senses

"Suru" can be used when the verb of the sentence involves one of the 5 senses of sight, smell, sound, touch, or taste:

Ii nioi ga suru.
いい匂いがする。
It smells good.
Nami no oto ga suru.
波の音がする。
I hear the sound of the waves.

Loan Word + Suru

Loan words are words adopted from another language phonetically. In Japanese, loan words are written using characters which sound similar to the original word. Loan words are often combined with "suru" to change them into verbs:

doraibu suru
ドライブする
to drive taipu suru
タイプする
to type
kisu suru
キスする
to kiss nokku suru
ノックする
to knock

Noun (of Chinese origin) + Suru

When combined with nouns of Chinese origin, "suru" turns the noun into a verb:

benkyou suru
勉強する
to study sentaku suru
洗濯する
to do the washing
ryokou suru
旅行する
to travel shitsumon suru
質問する
to ask questions
denwa suru
電話する
to telephone yakusoku suru
約束する
to promise
sanpo suru
散歩する
to take a walk yoyaku suru
予約する
to reserve
shokuji suru
食事する
to have a meal souji suru
掃除する
to clean
kekkon suru
結婚する
to get married kaimono suru
買い物する
to shop
setsumei suru
説明する
to explain junbi suru
準備する
to prepare

Note the particle "o" can be used as an object particle after a noun. (e.g. "benkyou o suru," "denwa o suru") There is no difference in meaning with or without "o."

Adverb or Onomatopoetic expression + Suru

Adverbs or onomatopoeic expressions combined with " suru" become verbs:

yukkuri suru
ゆっくりする
to stay long bon'yari suru
ぼんやりする
to be absent minded
nikoniko suru
ニコニコする
to smile waku waku suru
ワクワクする
to be excited