余分 (yobun) conjugation
extra, excess, surplus
余分 (よぶん, yobun) is a na-adjective. Na-adjectives behave like nouns. The word itself never changes — you conjugate だ/です after it, and you need な to put it in front of a noun.
Conjugation table
| Form | Plain (casual) | Polite (~です) | When you use it |
|---|---|---|---|
| Dictionary / plain | 余分だ yobunda | 余分です yobundesu | The form you look up. Also the casual “is ~”. |
| Negative | 余分じゃない yobunjanai | 余分じゃないです yobunjanaidesu | “is not ~”. |
| Past | 余分だった yobundatta | 余分でした yobundeshita | “was ~”. |
| Past negative | 余分じゃなかった yobunjanakatta | 余分じゃなかったです yobunjanakattadesu | “was not ~”. |
| Te-form | 余分で yobunde | — | Links to the next clause: “~ and …”. |
| Adverb | 余分に yobunni | — | Turns it into “~ly”, describing a verb. |
| Before a noun | 余分な〜 yobunna〜 | — | How it attaches when it modifies a noun. |
| Conditional (~ば/なら) | 余分なら yobunnara | — | “if it is ~”. |
| Conditional (~たら) | 余分だったら yobundattara | — | “if / when it is ~”. The everyday conditional. |
| Become (~なる) | 余分になる yobunninaru | 余分になります yobunninarimasu | “becomes ~” — the change-of-state form. |
| Too much (~すぎる) | 余分すぎる yobunsugiru | 余分すぎます yobunsugimasu | “too ~”. |
| Looks ~ (~そう) | 余分そう yobunsou | 余分そうです yobunsoudesu | “looks / seems ~” from appearance. |
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Why it conjugates this way
Na-adjectives behave like nouns. The word itself never changes — you conjugate だ/です after it, and you need な to put it in front of a noun.
See the full rules in the adjective conjugation guide.