乾く vs 乾かす
JLPT N4 vocabulary · what is the difference?
乾く is something drying on its own — the laundry dries, the paint dries — and the thing that dries is marked with が. 乾かす is a person drying something on purpose, and the thing being dried is marked with を: 髪を乾かす, "I dry my hair."
When to use each
乾く
かわく
Use 乾く when nothing is being done to the thing — air, sun or time does the work. The subject takes が, and there is never a を object.
洗濯物がまだ乾いていません。
せんたくものがまだかわいていません。
The laundry isn't dry yet.
ペンキが乾くまで触らないでください。
ペンキがかわくまでさわらないでください。
Please don't touch it until the paint dries.
乾かす
かわかす
Use 乾かす when someone actively dries something — with a dryer, a heater, a fire, or by putting it somewhere. The thing dried takes を.
ドライヤーで髪を乾かします。
ドライヤーでかみをかわかします。
I dry my hair with a hairdryer.
濡れた靴を一晩かけて乾かした。
ぬれたくつをひとばんかけてかわかした。
I dried the wet shoes overnight.
Sentences where only one works
この生地はすぐ乾きます。
このきじはすぐかわきます。
This fabric dries quickly.
A property of the fabric itself — no one is drying it, so 乾く.
タオルを日に当てて乾かします。
タオルをひにあててかわかします。
I dry the towel in the sun.
I put it there on purpose, so the towel is a を object of 乾かす.
髪がなかなか乾かないので、乾かしてから出かけます。
かみがなかなかかわかないので、かわかしてからでかけます。
My hair won't dry, so I'll dry it before going out.
The same hair twice: が乾かない for what it does by itself, を乾かす for what I do to it.
Common mistakes
洗濯物を乾きました。
洗濯物が乾きました。／洗濯物を乾かしました。
乾く never takes を. Say 乾きました if it dried on its own, 乾かしました if you dried it.
のどが乾きました。
のどが渇きました。
Both are read かわく, but thirst is 渇く. 乾く is for laundry, paint and air — not throats. People do sometimes type 喉が乾く casually, but 渇く is the correct spelling.
Frequently asked questions
What's the difference between 乾かす and 干す?
干す is specifically hanging something out — on a line, in the sun, on a rack. 乾かす is drying by any means, including a hairdryer or a heater. 洗濯物を干す is putting it out; 洗濯物を乾かす is getting it dry.
Is 乾いた a verb or an adjective in 乾いたタオル?
It's the past form of 乾く modifying a noun: "a towel that has dried" = a dry towel. That is the normal way to say "dry ~" in Japanese.
Can I say 私は洗濯物を乾きたい?
No. If you are the one doing it, it has to be 乾かしたい. 乾く has no doer, so it cannot take a を object.