How to Say "Helpful" in Japanese

役に立つ

yakunitatsu[ja̠kɯ̟ ɲ̟i ta̠t͡sɨ]

The English word 'helpful' is translated into Japanese as 役に立つ (yakunitatsu). Wiktionary also lists 有用 (yūyō).

Meaning: furnishing help, giving aid, useful (adj)

Ways to say it

“helpful” in Japanese
Japanese	Romanization (Wiktionary)	IPA
役に立つ	yakunitatsu	[ja̠kɯ̟ ɲ̟i ta̠t͡sɨ] (narrow)
有用	yūyō

役に立つ is used for both people (being helpful) and objects (being useful/handy).

While 役に立つ is a common, versatile way to say 'helpful', 有用 is a more formal, academic or technical term meaning 'useful' or 'of utility'.

The past tense of 役に立つ is 役に立った, used to say something 'was helpful'. The polite form of 役に立つ is 役に立ちます.

yakunitatsu

In Japanese, if someone performs a helpful act for you, the most natural way to acknowledge it is often to say 助かりました, which translates to 'I was saved'.
The word 役 in 役に立つ literally means 'role', 'duty', or 'service'. When you say something is helpful, you are figuratively saying it 'stands in a role' or 'fulfills a function'.
While 役に立つ is great for objects, if you want to praise a person for being helpful, using it can sometimes sound slightly cold or clinical, as if you are evaluating their efficiency like a tool.

それが役に立つと思いますか？
Do you think that would be helpful?
This sentence is useful for asking if something would be helpful.
Tatoeba #3388395 by e4zh1nmcz, translation #13481800 by CK
このページは役に立ちましたか？
Was this page helpful?
This sentence is useful for asking if a page was helpful.
Wiktionary
君の助言はいつも私の役に立つ。
Your advice is always helpful to me.
This sentence is useful for stating that advice is helpful.
Tatoeba #178203 by mookeee, translation #17055 by CK
彼女のアドバイスはとても有用でした。
Her advice was very helpful.
お忙しいところ、協力いただき、ありがとうございます。
Thank you for your cooperation even though you are busy.
いつもお世話になっています。
I always appreciate your continued help.
君は本当に頼りになるよ。
You are really reliable.
助けてくれて、どうもありがとう！
Thank you so much for helping me!
君のアドバイスはいつも役に立っているよ。
Your advice is always helpful.
1 more sentence on Tatoeba

Himari and Hinata are discussing a study method at a cafe.

陽葵 Himari

この参考書、すごく役に立つよ。
Kono sankousho, sugoku yaku ni tatsu yo.
This reference book is really helpful.
陽太 Yota

本当に？陽葵に勧められてよかった。
Hontou? Himari ni susumerarete yokatta.
Really? I'm glad you recommended it, Himari.
陽葵 Himari

試験の勉強に絶対役に立つと思う。
Shiken no benkyou ni zettai yaku ni tatsu to omou.
I think it will definitely be helpful for studying for the exam.
陽太 Yota

ありがとう、さっそく使ってみるね。
Arigatou, sassoku tsukatte miru ne.
Thanks, I'll try using it right away.

Sources

⭐Share⭐ to appreciate human effort 🙏