Translation guide
The English phrase "be useful" describes something that serves a purpose or helps achieve a goal. In Japanese, this concept is expressed through various adjectives, verbs, and set phrases, depending on whether you're talking about objects, people, skills, or abstract things. The most common and versatile word is 役に立つ (yaku ni tatsu), but other options like 便利 (benri) and 有用 (yūyō) are used in specific contexts.
Expressing that something or someone is helpful, beneficial, or serves a purpose in a practical way.
This is the most common and versatile way to say 'be useful'. It literally means 'to stand in a role/use'. It can be used for objects, information, skills, and people. Often used in the past tense 役に立った to mean 'was useful'.
この本はとても役に立つ。
This book is very useful.
彼のアドバイスが役に立った。
His advice was useful.
このアプリは日本語の勉強に役に立つ。
This app is useful for studying Japanese.
A na-adjective meaning 'convenient' or 'handy'. It emphasizes ease of use and practicality, often for tools, locations, or services. It's less about deep usefulness and more about making life easier.
この道具はとても便利だ。
This tool is very useful/handy.
駅の近くに住んでいて便利です。
It's convenient living near the station.
A na-adjective meaning 'useful' or 'beneficial', often used in formal or technical contexts. It implies objective value or utility, and is common in written language.
このデータは非常に有用である。
This data is extremely useful.
Expressing that a person is helpful or can be of assistance, often in a work or volunteer context.
Same as above, but specifically for people. It can sound a bit humble when referring to oneself.
彼はチームでとても役に立つ。
He is very useful to the team.
私にできることがあれば、役に立ちたいです。
If there's anything I can do, I want to be useful.
Literally 'to become strength', meaning to be helpful or supportive, often emotionally or through effort. It's warmer and more personal than 役に立つ.
Humble form of 役に立つ, used when offering help or services to a superior or customer. It's very polite.
何かお役に立てることがあれば、お知らせください。
Please let me know if there is anything I can do to be of service.
Expressing that something proves to be useful in a situation, often unexpectedly or in a pinch.
Again, 役に立つ works perfectly here. The context makes it clear it's about something coming in handy.
この小さなナイフがキャンプで役に立った。
This small knife came in handy during camping.
A verb meaning to find something very useful and convenient, often treasuring it for its utility. It implies a personal appreciation for the item's usefulness.
この辞書はいつも重宝している。
I always find this dictionary very useful.
このアプリは旅行中に重宝した。
This app came in really handy during the trip.
Describing something that serves as a good reference, guide, or source of information.
Literally 'to become a reference'. It means something is informative or helpful as a reference. Very common for books, websites, advice, etc.
この記事はとても参考になった。
This article was very informative/useful.
彼の意見は参考になる。
His opinion is useful as a reference.
Means 'to be beneficial' or 'to be good for one's growth/learning'. It's often used for educational or morally uplifting content.
この本はとてもためになる。
This book is very instructive/useful.
役に立つ (yaku ni tatsu) is about being helpful or serving a purpose, while 便利 (benri) is about convenience and ease. A Swiss Army knife is 便利 because it's compact and multi-functional; a textbook is 役に立つ because it helps you learn. Sometimes they overlap, but 便利 often implies a pleasant lack of effort.
このアプリは便利だけど、勉強の役には立たない。
This app is convenient, but it's not useful for studying.
The English loanword ユースフル (yūsufuru) exists but is very rare and sounds unnatural in most contexts. Stick to the Japanese expressions above.
このガイドは初心者に役に立つはずです。
This guide should be useful for beginners.
I'll always be there for you when you're in trouble. (lit. I'll be your strength.)
あなたの助けが本当に力になりました。
Your help was really a great support.