ようにする・
Personal decisions, habits, and external rules
Choose these forms by asking two questions: who controls what happens, and are you describing a new choice or something that continues? する forms usually keep the person's effort or decision in view. なる forms present a settled outcome, an arrangement already in force, or the way a system is designed to work. The continuing endings then distinguish an ongoing practice or existing setup from a newly adopted choice.
The whole system at a glance
First identify the controller: the person acting, a backgrounded decision maker, or a designed system. Then decide whether the sentence presents a new choice, a continuing practice, a settled outcome, or an existing arrangement.
A newly adopted effort
ようにする
Someone resolves to take care to perform or avoid a controllable action.
This emphasizes effort or precaution, not guaranteed success.
One personal decision
ことにする
The subject chooses a particular action or chooses not to act.
A settled decision or outcome
ことになる
What was decided, assigned, or brought about matters more than identifying the chooser.
People may still have made the decision; the sentence simply leaves them in the background.
An ongoing conscious effort
ようにしている
Someone actively tries to maintain a habit that takes attention, planning, or restraint.
A standing personal rule
ことにしている
Someone treats a chosen routine as a continuing personal policy.
An established external rule or schedule
ことになっている
A rule, convention, schedule, or arrangement already applies.
A built-in operation
ようになっている
A device, service, procedure, or system is designed to behave in a repeatable way.
New effort or maintained habit?
A person wants to walk outside during lunch for health reasons.
健康のため、今日から昼休みに外を歩くようにします。
For my health, starting today I'll make an effort to walk outside during lunch.
Analyze健康のため、昼休みにはできるだけ外を歩くようにしています。
For my health, I try to walk outside during lunch whenever possible.
AnalyzeTakeaway: ようにする adopts the effort now; ようにしている presents it as an effort being maintained. Neither form necessarily claims perfect success.
One decision or a standing personal policy?
A person chooses to take a walk after dinner.
今日は夕食後に散歩することにしました。
I've decided to take a walk after dinner today.
Analyze私は毎日、夕食後に散歩することにしています。
I make it a rule to take a walk after dinner every day.
AnalyzeTakeaway: ことにする presents the act of choosing. ことにしている says that the choice remains in effect as a regular personal rule.
The decision was reached, or the rule is now in force
ことになる focuses on a decision, assignment, or outcome being settled. ことになっている looks at the resulting arrangement as something that already applies. The first is common when announcing a development; the second is common when explaining workplace, school, facility, or schedule rules.
Human rule or system design?
ことになっている reports what people are expected or scheduled to do under an established arrangement. ようになっている explains what a machine, application, service, or procedure is built to allow, prevent, display, or perform.
Where the forms sound natural
The personal effort and decision forms are ordinary in conversation and general writing. The external-rule form is common in schools, workplaces, clubs, public facilities, and schedule explanations, where its backgrounded decision maker can sound usefully impersonal. The system-design form appears often in manuals, tours, customer explanations, and technical descriptions, but it is also natural in everyday conversation about how a device or service works.
More examples across the family
明日から、作業を始める前に手順を確認するようにします。
Starting tomorrow, I'll make an effort to check the procedure before beginning work.
Analyze今回は一人で応募することにしました。
This time, I've decided to apply on my own.
Analyze話し合いの結果、新人研修は六月に行うことになりました。
Following the discussion, it was decided that the new-employee training would be held in June.
Analyze私は毎週日曜日に、一週間の支出を確認することにしています。
I make it a rule to review my spending every Sunday.
Analyzeこの研究室では、最後に帰る人が窓を閉めることになっています。
In this laboratory, the last person to leave is responsible for closing the windows.
Analyze忙しい日でも、短い休憩を取るようにしています。
Even on busy days, I try to take short breaks.
Analyzeこのアプリでは、重要な更新だけが通知されるようになっています。
This application is set up to send notifications only for important updates.
Analyze