It Has Been Decided / It Turns Out That

Meaning & Usage

The grammar pattern ことになる (koto ni naru) describes an outcome, decision, or situation that has been determined. These determinations often stem from external factors, specific circumstances, or a natural progression of events. Unlike ことにする (koto ni suru), which expresses a personal decision made by the speaker, ことになる signifies a decision or development that the speaker is reporting, or one that has happened beyond their direct personal will or control.

You can think of ことになる as saying "it has been decided that...", "it turns out that...", "it will come to be that...", or "it has been arranged that...". The key nuance is the impersonal nature of the decision or outcome. The subject of the sentence (often implied) is not the one actively making the choice, but rather is subject to it. For example, if you say 「来週出張に行くことになる。」 (Raishū shucchō ni iku koto ni naru.), it implies that your boss or company decided you would go on a business trip next week, not that you personally chose to go.

This pattern is frequently used in both formal and informal contexts. In formal settings, it's ideal for announcing official decisions, new policies, or established rules. For instance, when a company announces changes to working hours or a school announces a new curriculum, ことになる is a common choice. It presents the information as a fixed outcome rather than a personal decree. In casual conversation, it might be used to describe how a situation naturally unfolded or an unexpected result, such as 「結局、残業することになった。」 (Kekkyoku, zangyō suru koto ni natta. - In the end, it turned out that I had to work overtime.).

A helpful way to think of ことになる is as conveying, "The situation dictates...", "The facts lead to...", or "The decision has been made that...". It allows speakers to report facts and outcomes objectively, without necessarily taking responsibility for them. This pattern is a common way to soften announcements or explain circumstances beyond one's individual control, making it a crucial pattern for describing externally determined events in Japanese.

Structure & Formation

The structure for ことになる (koto ni naru) is straightforward: it primarily attaches to the plain form of verbs.

As you can see, the most common and direct formation involves connecting ことになる to the plain form of a verb, regardless of tense (present/future, negative, or past). This flexibility allows you to express decisions or outcomes that are yet to happen, are currently not happening, or have already taken place.

For example:

• Verb (Present/Future Plain): 会議かいぎに参加さんかすることになる。

(Kaigi ni sanka suru koto ni naru.)

It has been decided that I will attend the meeting.

• Verb (Negative Plain): 明日あしたは学校がっこうへ行いかないことになる。

(Ashita wa gakkō e ikanai koto ni naru.)

It has been decided that I won't go to school tomorrow.

• Verb (Past Plain): 彼かれは転勤てんきんすることになった。

(Kare wa tenkin suru koto ni natta.)

It was decided that he would be transferred.

Remember that ことになる can also be conjugated to its past tense form, ことになった (koto ni natta), to indicate a decision or outcome that has already occurred.

Example Sentences

General Decisions & Outcomes

Unavoidable Situations / Natural Progression

Rules & Arrangements

Negative and Past Forms

Common Mistakes

Mistake 1: Confusing ことになる with ことにする

This is, without a doubt, the most common mistake. ことになる indicates an external decision or outcome, while ことにする expresses the speaker's personal decision or choice.

❌ 明日あしたからダイエットを始はじめることになる。

(Ashita kara daietto o hajimeru koto ni naru.)

✅ 明日あしたからダイエットを始はじめることにする。

(Ashita kara daietto o hajimeru koto ni suru.)

The first sentence implies that someone else decided you would start a diet, or it was decided by circumstances. The correct sentence, using ことにする, clearly states that you made the decision to start a diet.

Mistake 2: Using ことになる for a direct command or request

ことになる reports a decision or outcome; it doesn't issue a direct command or request. While it can report that a rule is in place, it's not used to tell someone what to do directly.

❌ 資料しりょうを明日あしたまでに提出ていしゅつすることになる。

(Shiryō o ashita made ni teishutsu suru koto ni naru.)

✅ 資料しりょうを明日あしたまでに提出ていしゅつしてください。

(Shiryō o ashita made ni teishutsu shite kudasai.)

The first sentence sounds like you are reporting a decision about the documents, not telling someone to submit them. A direct request or command (like using 「～てください」) is more appropriate here.

Mistake 3: Incorrectly conjugating the verb before ことになる

Remember that ことになる attaches to the plain form of a verb. Forgetting to use the plain form or using a polite form is a common error.

❌ 来週らいしゅう、大阪おおさかへ行いきますことになる。

(Raishū, Ōsaka e ikimasu koto ni naru.)

✅ 来週らいしゅう、大阪おおさかへ行いくことになる。

(Raishū, Ōsaka e iku koto ni naru.)

The verb 「行いきます」 is the polite form. It needs to be converted to its plain form, 「行いく」, before attaching ことになる.

Mistake 4: Using ことになる for obvious future events without external decision

While ことになる can refer to future events, it emphasizes an external decision or outcome. For simple, obvious future events, a regular future tense might be more natural.

❌ 明日あしたは雨あめが降ふることになる。

(Ashita wa ame ga furu koto ni naru.)

✅ 明日あしたは雨あめが降ふるでしょう。

(Ashita wa ame ga furu deshō.)

Unless there's some external decision making it rain (which is highly unlikely!), using ことになる sounds unnatural. Simple future tense or probability expressions are usually better for weather forecasts.

Cultural Notes

In Japanese communication, direct statements of personal responsibility or volition can sometimes be softened to maintain harmony or show humility. ことになる serves as an effective tool for this purpose. By using this grammar pattern, a speaker can present a situation or decision as an external fact or an outcome of circumstances, rather than something they personally initiated or are solely responsible for. This can be particularly useful in professional environments or when delivering news that might be unfavorable.

For instance, instead of saying 「私わたしは転勤てんきんします。」 (Watashi wa tenkin shimasu. - I will transfer.), which sounds like a personal choice, saying 「転勤てんきんすることになりました。」 (Tenkin suru koto ni narimashita. - It has been decided that I will transfer.) conveys that the transfer is a company decision, not something the individual chose. This subtle difference is very important in Japanese business etiquette, as it shows you are following company policy rather than just doing what you want.

Furthermore, ことになる is frequently used when discussing rules, laws, or established procedures. It frames these as existing facts that apply universally, reinforcing their impersonal and objective nature. This contributes to the clarity and formality often desired in official announcements or explanations.

JLPT Tips

For the JLPT N3 exam, understanding the distinction between ことになる and ことにする is crucial. Many questions will test your ability to correctly identify when a decision is personal versus when it is external or circumstantial. Always ask yourself: "Who made this decision or what caused this outcome?" If the answer is "I did" or "I chose to," then ことにする is likely correct. If the answer is "It was decided by others," "Circumstances led to this," or "It just turned out this way," then ことになる is the correct choice.

Pay close attention to the verb conjugation preceding ことになる. It must always be in its plain form (dictionary form, ない-form, た-form). Incorrectly using polite forms (like ～ます) is a common trap on the exam. Quickly identify the verb and convert it to its plain form before considering ことになる.

Also, be aware of the context. Sentences describing rules, company policies, unexpected events, or consequences of actions are strong indicators that ことになる is appropriate. Look for keywords that suggest an external force, like 「会社かいしゃで」 (at the company), 「法律ほうりつで」 (by law), 「雨あめのため」 (due to rain), or expressions of surprise or realization. Mastering ことになる will greatly improve your comprehension of nuanced Japanese sentences.