〜ておく: Doing Something in Advance (Meaning + Examples)
What it means
〜ておく attaches to a verb's て-form and adds the idea that you do the action on purpose, ahead of time — either to get ready for something later, or to deliberately leave a situation as it is. The verb おく on its own means "to put/place," and that sense of "setting something in place for later" carries over.
There are two everyday meanings, and which one you mean is usually clear from context:
旅行の前にホテルを予約しておく。
りょこうの まえに ホテルを よやくして おく。
I'll book the hotel in advance before the trip.
Preparation: do it now so it's ready later.
ヤッタンは窓を開けておいた。
ヤッタンは まどを あけて おいた。
Yattan left the window open.
Leaving a state as it is — open it and let it stay open.
Meaning 1 — doing something in advance
The most common use is preparing for the future. You do the action now so that things are ready when the time comes:
テストの前に単語を覚えておきます。
テストの まえに たんごを おぼえて おきます。
I'll memorize the vocabulary in advance before the test.
モチはパーティーのために飲み物を買っておいた。
モチは パーティーの ために のみものを かって おいた。
Mochi bought drinks ahead of time for the party.
Past 〜ておいた = did it in advance.
先生に質問を考えておきました。
せんせいに しつもんを かんがえて おきました。
I thought up some questions for the teacher in advance.
This often pairs with 〜前に ("before…") because both point at getting ready.
Meaning 2 — leaving something as it is
The second use is letting a state continue — you do something and then choose not to change it. 窓を開けておく isn't "open the window in advance"; it's "open the window and leave it open":
暑いから、ドアを開けておいてください。
あついから、ドアを あけて おいて ください。
It's hot, so please leave the door open.
その本はそこに置いておいて。
その ほんは そこに おいて おいて。
Just leave that book there.
置いて (put) + おいて — yes, おく twice; totally natural.
How to form it
Just swap the final く of おく through the normal verb conjugations. Everything builds off the て-form:
| Form | Pattern | Example |
|---|---|---|
| Plain | 〜ておく | 予約しておく (book in advance) |
| Polite | 〜ておきます | 予約しておきます |
| Past | 〜ておいた | 予約しておいた (booked in advance) |
| Polite past | 〜ておきました | 予約しておきました |
| Negative | 〜ておかない | 予約しておかない |
| Want to | 〜ておきたい | 予約しておきたい (want to book in advance) |
When the て-form ends in 〜で (verbs like 読む → 読んで, 飲む → 飲んで), it becomes 〜でおく: 読んでおく ("read it in advance").
〜ておきたい — wanting to do it in advance
Combine おく with 〜たい and you get 〜ておきたい = "want to do (something) ahead of time":
出かける前にご飯を食べておきたい。
でかける まえに ごはんを たべて おきたい。
I want to eat before I go out.
The casual contraction 〜とく
In everyday speech, 〜ておく squeezes down to 〜とく. This is extremely common — you'll hear it constantly:
| Form | Core idea | Example |
|---|---|---|
| 〜ておく → 〜とく | casual contraction | 買っておく → 買っとく = I'll buy it (in advance) |
| 〜でおく → 〜どく | after で-type て-forms | 読んでおく → 読んどく = I'll read it (in advance) |
| 〜ておいた → 〜といた | past, casual | やっておいた → やっといた = did it ahead of time |
ヤッタンの弟が「お菓子、買っとくね」と言った。
ヤッタンの おとうとが 「おかし、かっとくね」と いった。
Yattan's little brother said, 'I'll buy the snacks in advance, okay.'
買っとく = casual 買っておく.
Keep 〜とく for friends and casual chat; use 〜ておきます when you need to be polite.
Common mistakes
- Forgetting the で-form switch. With 読む, 飲む, 遊ぶ, etc., it's 読んでおく, not 読んておく — and casually 読んどく.
- Mixing up おく with 〜てある (te-aru). 〜ておく is the deliberate action of preparing; 〜てある describes the resulting state (窓が開けてある = "the window has been opened"). Related, but not the same.
- Reading 開けておく as "open in advance." With many verbs the meaning is "do it and leave it that way" — context decides between "in advance" and "leave as is."
- Using ます in the wrong spot. Conjugate おく, not the first verb: 予約しておきます (✓), not 予約しますておく (✗).
Quick recap
- 〜ておく = て-form + おく: do something in advance, or leave it as it is.
- Past 〜ておいた = did it ahead of time; 〜ておきたい = want to do it ahead of time.
- After 〜で て-forms it's 〜でおく.
- Casual contraction: 〜とく (買っとく) and 〜どく (読んどく).
Your turn
Choose the correct 〜ておく form (advance / leave-as-is / casual 〜とく).
Start the 5-question drill →Frequently asked questions
What's the difference between the two meanings of 〜ておく?
One is preparation — doing something now so it's ready later (ホテルを予約しておく, 'book the hotel in advance'). The other is leaving a state alone (窓を開けておく, 'leave the window open'). Context tells you which one is meant.
What does 〜とく mean?
〜とく is the casual spoken contraction of 〜ておく: 買っておく becomes 買っとく. After で-type て-forms it's 〜どく (読んでおく → 読んどく). Use the full 〜ておきます when you need to be polite.
How do I say I did something in advance?
Use the past form 〜ておいた (plain) or 〜ておきました (polite): 飲み物を買っておいた ('I bought drinks ahead of time'). Casually, 買っといた.
Is 〜ておく the same as 〜てある?
They're related but different. 〜ておく is the deliberate action of preparing or leaving something. 〜てある describes the resulting state (窓が開けてある, 'the window has been left open').