Examples
Meaning
〜ことになる means it has been decided that or it will turn out that. It often describes a decision, arrangement, or result that is not presented as the speaker's personal decision alone.
Formation
Use the dictionary form or negative form of a verb before ことになる. In polite speech, ことになります or ことになりました is common.
Usage
Use this pattern for company decisions, school rules, schedules, assignments, or arrangements decided by a group or outside circumstances. It is common in announcements and polite explanations.
Nuance
The speaker often sounds less directly responsible for the decision. This makes the expression useful when the decision came from a workplace, family, schedule, or situation.
Comparison
Compared with 〜ことにする, 〜ことになる does not emphasize the speaker's own decision. 来月転勤することになりました means it has been decided that I will transfer next month. 来月転勤することにしました means I decided to transfer next month.
Common Mistakes
A common mistake is using 〜ことになる for a personal choice the speaker actively made. If you want to emphasize your own decision, use 〜ことにする.
Related Grammar
〜ことにする
〜ことにする means to decide to do or not do something. It emphasizes the speaker's or subject's own decision.
〜ことになっている
〜ことになっている describes a rule, arrangement, schedule, or established decision that is already in place.
〜ことにする・〜ことになるの違い
This page explains the difference between 〜ことにする and 〜ことになる: deciding by oneself versus having something decided or arranged.
〜ようになる・〜ことになるの違い
This page compares 〜ようになる and 〜ことになる, two patterns that can both describe change but focus on different kinds of change.