役立つ（やくだつ）Conjugation
JLPT N3 · Godan verb (Group 1) · Meaning: to be useful
Full conjugation table
| Form | Japanese | Reading |
|---|---|---|
| Dictionary form The base form — casual speech and the stem for many grammar patterns. | 役立つ | やくだつ |
| masu (polite present) Polite present/future affirmative. | 役立ちます | やくだちます |
| masen (polite negative) Polite present negative. | 役立ちません | やくだちません |
| mashita (polite past) Polite past affirmative. | 役立ちました | やくだちました |
| masen deshita (polite past neg.) Polite past negative. | 役立ちませんでした | やくだちませんでした |
| te-form The most versatile form — linking, requests, progressive and more. | 役立って | やくだって |
| ta (plain past) Plain past affirmative. | 役立った | やくだった |
| nai (plain negative) Plain present negative. | 役立たない | やくだたない |
| nakatta (plain past neg.) Plain past negative. | 役立たなかった | やくだたなかった |
| Potential Ability or possibility — 'can do'. | 役立てる | やくだてる |
| Passive Passive voice — 'to be done to'. | 役立たれる | やくだたれる |
| Causative Causative — 'to make/let someone do'. | 役立たせる | やくだたせる |
| Volitional Volitional — 'let's…' or intention. | 役立とう | やくだとう |
| Imperative Imperative — a strong command; used sparingly. | 役立て | やくだて |
| Prohibitive Prohibitive — 'don't do it!'. | 役立つな | やくだつな |
| Conditional (ba) Hypothetical 'if' — leans written. | 役立てば | やくだてば |
| Conditional (tara) The most versatile everyday 'if / when'. | 役立ったら | やくだったら |
Example sentences
- この辞書は勉強に役立つ。 — This dictionary is useful for studying.
- 旅行で覚えた言葉が役立った。 — The words I learned while traveling came in handy.