減らす (herasu) conjugation
to decrease, to diminish
減らす (へらす, herasu) is a godan verb. Godan verbs change their final kana up and down its column of the kana chart — the a-row for negatives, the i-row before ます, the e-row for potential and ば. Every form below is tappable — hear it, then say it back.
Conjugation table
| Form | Plain (casual) | Polite (~ます) | When you use it |
|---|---|---|---|
| Dictionary / plain | 減らす herasu | 減らします herashimasu | The form you look up. Also the casual present and future. |
| Plain negative | 減らさない herasanai | 減らしません herashimasen | “doesn’t / won’t”. From here it conjugates like an i-adjective. |
| Plain past | 減らした herashita | 減らしました herashimashita | The casual past — same ending as the te-form, with た/だ. |
| Plain past negative | 減らさなかった herasanakatta | 減らしませんでした herashimasendeshita | “didn’t”. The negative past, still i-adjective-shaped. |
| Te-form | 減らして herashite | — | The connector: requests, linking clauses, ~ている. |
| Progressive (~ている) | 減らしている herashiteiru | 減らしています herashiteimasu | “is ~ing”, or an ongoing resulting state. |
| Desire (~たい) | 減らしたい herashitai | 減らしたいです herashitaidesu | “want to ~”. Behaves as an i-adjective. |
| Volitional | 減らそう herasou | 減らしましょう herashimashou | “let’s ~” / “I think I’ll ~”. |
| Potential | 減らせる heraseru | 減らせます herasemasu | “can ~”. What you could do; the object often takes が. |
| Passive | 減らされる herasareru | 減らされます herasaremasu | “is ~ed”. Also the honorific and the suffering passive. |
| Causative | 減らさせる herasaseru | 減らさせます herasasemasu | Make or let someone do it. |
| Causative-passive | 減らさせられる herasaserareru | 減らさせられます herasaseraremasu | Be made to do it — the long one. |
| Imperative | 減らせ herase | 減らしてください herashitekudasai | Blunt order. Use ~てください in real life. |
| Prohibitive | 減らすな herasuna | — | “don’t!” — dictionary form + な. |
| Conditional (~ば) | 減らせば heraseba | — | “if ~”. General rules and hypotheticals. |
| Conditional (~たら) | 減らしたら herashitara | — | “if / when ~”. The everyday conditional. |
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Why it conjugates this way
Godan verbs change their final kana up and down its column of the kana chart — the a-row for negatives, the i-row before ます, the e-row for potential and ば.
See the full rules on the verb conjugation guide.