こと Patterns Compared – Japanese Cheat Sheet

こと (written as こと or 事) turns verbs into noun clauses. Four patterns look almost identical ことがある, ことにする, ことになる, ことができる, but they have completely different meanings. Mixing them up changes what you're saying dramatically.

Pattern	Meaning	Who decides?	Verb form
〜ことがある	sometimes / have experienced	n/a	Dictionary (sometimes) / た-form (experience)
〜ことにする	decide to / have decided to	speaker decides	Dictionary form
〜ことになる	it has been decided that / it will turn out that	externalnatural	Dictionary form
〜ことができる	can / be able to	n/a	Dictionary form

1. 〜ことがある "sometimes" or "have done before"

This pattern has two distinct uses depending on verb tense. With dictionary form, it means something happens occasionally ("there are times when"). With た-form, it means you have the experience of having done something at some point.

Dictionary form → "sometimes"

仕事しごとが遅おそくなることがある。Work sometimes runs late. (occasional occurrence)

朝あさご飯はんを食たべないことがある。I sometimes don't eat breakfast. (negative + ことがある)

た-form → "have the experience of"

富士山に登っのぼったことがある。I have climbed Mt. Fuji (before).

日本に行っいったことがありません。I have never been to Japan.

この映画えいがを見みたことがある？Have you seen this movie (before)?

2. 〜ことにする "I've decided to" (speaker's choice)

The speaker actively makes a decision. The choice is yours. ことにした = decided (past). ことにします = deciding now or going to decide. Very common for announcing personal plans or changes in behavior.

毎朝まいあさ走るはしることにしました。I've decided to run every morning. (personal decision)

お酒おさけをやめるやめることにした。I decided to quit drinking. (lifestyle change, self-chosen)

来年らいねんから日本語にほんごを勉強べんきょうすることにします。I'm going to start studying Japanese from next year.

この件けんは忘れるわすれることにしよう。Let's decide to forget about this matter.

3. 〜ことになる "it's been decided" (external/natural outcome)

The decision or outcome comes from outside the speaker a company, fate, circumstances. The speaker didn't choose it; it just came to be that way. Very common in Japanese workplaces and formal announcements, because it lets you report news without claiming personal responsibility.

来月らいげつから大阪おおさかに転勤てんきんすることになりました。It has been decided that I will transfer to Osaka next month. (company decision, not mine)

会議かいぎは中止ちゅうしになることになった。The meeting has been cancelled. (circumstances decided it)

いろいろあって、結婚けっこんすることになりました。One thing led to another, and we've decided to get married. (natural course of events)

このルールは廃止はいしされることになっています。This rule is scheduled to be abolished. (established plan, not personal)

4. 〜ことができる "can / be able to"

Expresses ability or possibility. Interchangeable with the potential verb form (e.g. 食べられる), but ことができる is more formal and explicit common in written language, resumes, and careful speech.

日本語にほんごを話すはなすことができます。I can speak Japanese.

ここに駐車ちゅうしゃすることができません。You cannot park here.

このアプリで予約よやくすることができる。You can make a reservation with this app.

あきらめずにいれば、夢ゆめを叶えるかなえることができる。If you don't give up, you can make your dreams come true.

ことにする vs ことになる the key distinction

This is the most commonly confused pair. The difference: にする = you chose it. になる = it happened externally.

ことにしました (I decided)

日本にほんに行くいくことにしました。

I decided to go to Japan. (my own choice)

ことになりました (it was decided)

日本にほんに行くいくことになりました。

It was decided that I'd go to Japan. (company sent me / circumstances led to it)

Japanese people often prefer ことになりました even for their own decisions in professional settings it sounds more humble, as if the situation decided rather than your own ego.

Quick map: ことがある (experience or habit) → ことができる (ability) → ことにする (I decided) → ことになる (externally decided). The にする/になる distinction is the one to really internalize.