Grammar Info

N3 Lesson 3: 10/22


It will end up being, It is the result of, It has been decided that

The "something has been decided" meaning only applies to verbs!


Verb + ことになる
[い]Adjective + ことになる
[な]Adjective + + ことになる


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About ことになる

ことになる is an expression that combines the nominalizing use of こと (creating a noun-phrase), with the case marking particle , and the う - Verb なる 'to become'. This expression can be translated as 'to become (A)', but has the nuance that someone/thing caused (A) to become that way. Due to this, it may also be translated as 'it has been decided that (A)', or 'it will end up being (A)'.
ことになる is primarily used with verbs and い-Adjectives in their attributive form. It may also be used with な-Adjectives followed by な.
  • なんでも後回(あとまわ)ているあとから苦労(くろう)することになる
    If you wait until it is too late, you are going to end up regretting it.
  • そんなことたらとんでもないことになるよ。
    If you do something like that, it is going to become a huge deal.
  • 出来(でき)だけ(はや)治療(ちりょう)ないと(あと)から大変(たいへん)ことになる
    If you don't treat it soon, it is going to end up being a bigger issue.
The 'it has been decided that (A)' meaning only applies to verbs, as only verbs will be enacted by someone/thing.
Fun Fact
This structure is a good example of why なる is often viewed as the intransitive form of する. する conveys that someone is performing an action (transitive), while なる implies that something is the result of an action (intransitive). This is why the (A) phrase in ことになる is usually determined to have been decided/performed by someone else, while still focusing on exactly 'what' (A) became.


  • 明日(あした)(あめ)ならば、1週間(しゅうかん)()(つづ)ことになる

    If it rains tomorrow, it will end up being a week straight of rain.

    Notice that when ことになる means 'end up' or 'it is the result of', it is often preceded by a conditional clause. Also, it often expresses a negative situation.

  • 震災(しんさい)のため、アメリカ(かえ)らなければならないことになりました

    It was decided that I must return to America because of the earthquake.

  • インフルエンザにかかってしまったので、今日(きょう)大会(たいかい)()れないことになった

    Since I got the flu I ended up being unable to attend today's tournament.

  • 大変(たいへん)ことになったぞ。(なに)作戦(さくせん)(かんが)えなければ。

    We ended up getting in trouble. We have to figure out a plan.

  • この(まえ)のように風邪(かぜ)()いたら、また入院(にゅういん)することになる

    If you catch a cold like the last time, you will end up going to the hospital again.

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ことになる – Grammar Discussion

Most Recent Replies (1 in total)

  • Talos


    While showing this grammar point to my Japanese-native tutor, she claimed that several of the sentences didn’t make sense to her.


    After I explained the meaning in English she said it would have made more sense ending in 続いたことになる 。


    She explained that 出れない normally only takes a human subject, so I should replace が with に to get 今日の大会に出れない

    Finally, my tutor also felt that this grammar point covered two very different usages and suggested that the “was decided” meaning acts as a single grammatical unit


    and tends to be used in the context of a business doing the deciding. (Your example sentences might support this depending on context.)

    From example sentences with decided meaning

    • Must return to America (from a business trip?)

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