足す|たすtasu[0]heiban (flat)
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Definitions
- godan verb, transitive verbto add (numbers)６０にするためには１７に何を足せばよいの。↗What do you have to add to 17 to get 60?
- godan verb, transitive verbto add (something); to top up (with something)
- godan verb, transitive verbto take care of (e.g. one's business)
Conjugation
| Dictionary form | 足す（たす） |
|---|---|
| Polite (masu) | 足します（たします） |
| Negative (nai) | 足さない（たさない） |
| polite (masen) | 足しません（たしません） |
| classical zu / nu | 足さず・足さぬ（たさず・たさぬ） |
| Past (ta) | 足した（たした） |
| polite (mashita) | 足しました（たしました） |
| Past negative (nakatta) | 足さなかった（たさなかった） |
| polite (masen deshita) | 足しませんでした（たしませんでした） |
| Te form | 足して（たして） |
| Potential | 足せる（たせる） |
| Passive | 足される（たされる） |
| Causative | 足させる（たさせる） |
| Causative passive | 足させられる（たさせられる） |
| Conditional (ba) | 足せば（たせば） |
| tara | 足したら（たしたら） |
| Volitional | 足そう（たそう） |
| polite (mashou) | 足しましょう（たしましょう） |
| Imperative | 足せ（たせ） |
Common forms generated by rule; see the senses for honorific or irregular usage.
Transitive / intransitive pair
お金を足す
足りる expresses that an amount or number is sufficient as it is; 足す means to add something in order to reach a required amount.
人数が足る
人数を足す
足る likewise indicates that a quantity or number is sufficient; 足す refers to the act of adding to make it sufficient.
Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only
Synonyms & antonyms
- Synonym加えるくわえるNeutralBroader than 「足す」: it also covers adding people to a group, exerting influence, or intensifying a degree. For plain topping up or adding numbers, either works.
- SynonymプラスNeutralA loanword, often used to read the + sign in equations or to mean 'on top of that'; as a noun it can mean a positive number or an advantage.
- Synonym合計ごうけいNeutralFocuses on adding several numbers together to get a total; 「足す」 refers only to the act of adding something on.
- Synonym加算かさんWrittenA written Sino-Japanese word for arithmetic addition or an added charge, as in 「料金を加算する」.
- Synonym合算がっさんWrittenWritten-style word for combining several items and calculating them together, as in 「所得を合算する」.
- Synonym添加てんかWrittenA written word mostly for adding substances to food or materials, as in 「食品添加物」.
- Synonym付け足すつけたすNeutralFocuses on adding something extra to what is already there, such as appending a sentence of explanation.
- Synonym付加ふかWrittenWritten word for attaching something on top, as in 「付加価値」; mostly seen in formal prose.
- Related増すますWrittenA written-style word focused on quantity or degree growing; it can be intransitive, while 「足す」 is someone deliberately adding.
- Antonym減らすへらすNeutralAntonym of 「足す」 in the sense of increasing an amount: it means to make a quantity smaller.
For everyday topping up and adding numbers, use 「足す」. Use 「加える」 when the sense is broader — adding people, influence, or degree. To get a total, use 「合計」. In formal prose, 「加算」 adds amounts or charges and 「付加」 attaches something on top.
Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only
Japanese definitions
Kanji in this word
English equivalents
See also
