Learn How to Conjugate the Japanese Verb "Suru"

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

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