Verb Conjugation「買う(かう、kau)」buy, will buy | Learn Japanese Grammar

Japanese verbs have conjugations.「買う(かう、kau)」is a verb and means “buy” or “will buy.” We will teach you the conjugation on this page. You can also learn example sentences using verb conjugations.

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Vocabulary Video

Before you learn the conjugations, please learn about the pronunciation of the verb in dictionary and ます forms.

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Dictionary Form/ます Form

As you know, English tenses are roughly divided into present, future, and past tenses. However, it is said that Japanese tenses consist only of “Past Tense” and “Non-Past Tense.” Therefore, we used “Dictionary Form,” not “Present Tense” in this heading.
Japanese people use two types of language. One is “non-honorific language” and the other is “honorific language.” When we focus on these languages, “dictionary” and “plain” forms are in “non-honorific language.” “Polite form” is in honorific language.

English Meaning: buy, will buy

Positive	Conjugation	Romaji Reading
Dictionary & Plain Form	買かう	kau
ます & Polite Form	買かいます	kaimasu

「辞書じしょ形けい (dictionary form)」is the original form. The technical term is for non-native Japanese speakers. Therefore, native Japanese usually do not know the word.「ます形けい (ます form)」is the polite form of a dictionary form. The term is also for non-native Japanese speakers.

I’ll buy a washing machine tomorrow morning.

明日あした、午前中ごぜんちゅうに洗濯機せんたくきを買う。 (Plain Form)
明日、午前中に洗濯機を買います。(Polite Form)

English Meaning: do not buy, will not buy

Negative	Conjugation	Romaji Reading
Plain Form	買かわない	kawanai
Polite Form	買いません	kaimasen

I won’t buy a washing machine this year.

今年ことしは洗濯機せんたくきを買わない。(Plain Form)
今年は洗濯機を買いません。(Polite Form)

Past Tense

English Meaning: bought

The plain form is in “た form”. “た form” is also a technical term for non-native Japanese speakers. Therefore, native Japanese usually do not know the word.

Positive	Conjugation	Romaji Reading
た & Plain Form	買かった	katta
Polite Form	買いました	kaimashita

My father bought a car yesterday.

昨日きのう、父ちちが車くるまを買った。(Plain Form)
昨日、父が車を買いました。(Polite Form)

English Meaning: did not buy

Negative	Conjugation	Romaji Reading
Plain Form	買かわなかった	kawanakatta
Polite Form	買いませんでした	kaimasen deshita

My father didn’t buy a car yesterday.

昨日きのう、父ちちは車くるまを買なかった。(Plain Form)
昨日、父は車を買いませんでした。(Polite Form)

て Form

English Meaning: N/A

We cannot know the exact meaning without knowing the sentence and situation.

	Conjugation	Romaji Reading
て Form	買かって	katte

About the phrases「ている」and「ています」: Here
About the phrase「～てください。」: Here

I bought a cake and went to my friend’s house.

ケーキを買って、友達ともだちの家いえに行いきました。(Polite Form)

In this case,「て」indicates “and” or “after.”

Volitional Form 1: Will, (Own) Intention, Determination

English Meaning: will buy

	Conjugation	Romaji Reading
Plain Form	買かおう	kaō
Polite Form	N/A	N/A

This phrase is used only in plain form. This is because we use it when we talk to ourselves or think in our minds. When we talk or think to ourselves, we usually do not use the polite form.

I’ll buy a bicycle next month.

来月らいげつ、自転車じてんしゃを買おう。(Plain Form)

Volitional Form 2: Solicitation, Intention, Invitation

English Meaning: let’s buy

	Conjugation	Romaji Reading
Plain Form	買かおう	kaō
Polite Form	買いましょう	kaimashō

Let’s buy some crepes in Harajuku!

原宿はらじゅくでクレープを買おう。(Plain Form)
原宿でクレープを買いましょう。(Polite Form)

Imperative Form

English Meaning: buy! (order, command)

Positive	Conjugation	Romaji Reading
Plain Form	買かえ	kae

Buy these shoes!

この靴くつを買え。(Plain Form)

“Imperative form” is used only in plain form and this phrase often becomes rude depending on the situation. Please show us your Japanese when you use it. We will check and teach suitable Japanese.
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Prohibition and Order

English Meaning: do not buy!

Negative	Conjugation	Romaji Reading
Plain Form	買かうな	kauna

Don’t buy expensive things!

高たかい物ものを買うな。(Plain Form)

Conditional Form

English Meaning: if (subject) buy

Conjugation	Romaji Reading
買かえば	kaeba

If you buy a fan, it will be cooler.

扇風機せんぷうきを買えば、涼すずしくなるでしょう。(Polite Form)

Hypothetical/Definite Conditions, Sequence of Actions

English Meanings: if/when ~ buy, ~ bought and ~

The form「～たら」has different usages. It has other meanings except from those listed above. More explanations are in our conversation lessons or mail support.

Conjugation	Romaji Reading
買かったら	kattara

Here is an example sentence wherein「たら」indicates a “sequence of actions.”

I bought a new microwave and cooking became easier.

新あたらしい電子でんしレンジを買ったら、料理りょうりが楽らくになりました。(Polite Form)

Causative Form

English Meaning: make/let/have (person) buy

Positive	Conjugation	Romaji Reading
Plain Form	買かわせる	kawaseru
Polite Form	買わせます	kawasemasu

I’ll let my boyfriend buy our wedding ring.

彼氏かれしに結婚指輪けっこんゆびわを買わせる。(Plain Form)
彼氏に結婚指輪を買わせます。(Polite Form)

English Meaning: do not make/let/have (person) buy

Negative	Conjugation	Romaji Reading
Plain Form	買かわせない	kawasenai
Polite Form	買わせません	kawasemasen

I won’t let my son buy alcohol.

息子むすこにお酒さけを買わせない。 (Plain Form)
息子にお酒を買わせません。(Polite Form)

Potential Verb

「可能かのう動詞どうし (potential verb/s)」is a verb classification that indicates “be able to” or “can do something.”「書ける(かける、kakeru)」is one of the potential verbs.「書く」and「書ける」are different verbs in Japanese. The details of the potential verb「書ける」is here:

To Learn Correct Verb Conjugations

Japanese verb conjugation is too complicated and there are many learners who use it incorrectly. Therefore, we provide lessons and services where we teach and correct your Japanese daily. If you want to know more about the details, please check out our website.
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