A casual, spoken contraction of 〜ておく / 〜でおく, used to express doing something in advance for a future purpose, or leaving something in a particular state.
Verb [て-form] + とくPrimary
Verb [て-form] + どく
This is a short way to say "to do something ahead of time." It also means to leave something as it is.
旅行の前に、ホテルの予約をしとくね。
I'll go ahead and book the hotel before our trip, okay?
昨日のうちに宿題やっといたから、今日は遊べる！
I already did my homework yesterday, so I can hang out today!
テストの前にこの本、読んどかないとヤバいよ。
It'll be bad if I don't read this book before the test.
時間があるうちに、この本を読んどこうかな。
Maybe I should go ahead and read this book while I have time.
おい、これ、さっさと片付けとけ！
Hey, clean this up right now!
Think of it like a sound rule. If the verb's 'te-form' ends with a 't' sound, you use 'toku'. If it ends with a 'd' sound, you use 'doku'.
This is different from 〜ておく. 〜ておく is more polite. Use 〜とく / 〜どく only with friends. Do not use it with your boss or teacher.
Don't use this when you write formal papers. For example, do not use it in reports or business emails.
Less formal alternatives(1)
Dialect / slang variants(1)
Track your mastery
Kumi's KMT system tracks your mastery across kanji, vocabulary, grammar, and reading. Create a free account to use it on 220,000+ concepts.