〜ておく: Doing Something in Advance (Meaning + Examples)
The extra meaning 〜ておく lays on the verb
〜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 onto whatever verb it follows.
Which of the two readings you get 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.
Preparation is the more common reading. 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 preparation sense often pairs with 〜前に ("before…") because both point at getting ready.
Leaving as is is the second reading — 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.
Which verbs it pairs with, and how it attaches
〜ておく rides on any volitional (deliberately controllable) verb — you're doing the action on purpose, so it fits verbs of preparing (予約する, 覚える, 買う, 考える) and of setting a state (開ける, 置く). To build it, just swap the final く of おく through the normal verb conjugations. Everything grows 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"). Note that you always conjugate おく, never the first verb: 予約しておきます (✓), not 予約しますておく (✗).
In use: 〜ておきたい and the casual 〜とく
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.
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.
How it differs from the plain verb and 〜てある
Against the plain verb, おく adds the deliberate "and leave it that way" layer: 開ける is just "open," while 開けておく is "open it and let it stay open." Because of this, don't read 開けておく as "open in advance" — with many verbs the meaning is "do it and leave it," and context decides between "in advance" and "leave as is."
The neighbour to keep separate is 〜てある (te-aru). 〜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 opened / left open"). Same scene, but ておく films the verb and てある films the result — related, not interchangeable.
One last form trap: with 読む, 飲む, 遊ぶ, etc., remember the で-switch — 読んでおく (not 読んておく), and casually 読んどく.
The short version
- 〜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).
Practice it
Choose the correct 〜ておく form (advance / leave-as-is / casual 〜とく).
＿＿＿に入れるのに最もよいものを選びなさい。
Choose the grammar pattern that best completes the sentence.
旅行の前に、ホテルを予約し＿＿＿。
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').
Where 〜ておく fits
Shaky on this? Get these solid first
- 〜てください · N5 — 〜てください is the standard way to politely ask someone to do something ('please do…'). Learn the formation, the negative 〜ないでください, softer variations, and see clear examples.
- The て-form · N5 — The て-form is the gateway to dozens of Japanese grammar patterns. Learn the conjugation rules for every verb group, the famous song trick, and see clear examples.
Don't confuse it with
- 〜ている · N5 — 〜ている has two big jobs: an ongoing action ('is doing') and a continuing state ('is in a state'). Learn when it means which, how to form it, and see clear examples.
Once this clicks, go on to
- 〜たい · N5 — 〜たい attaches to a verb stem to say what you want to do. Learn the formation, why it conjugates like an i-adjective, the が/を switch, how to talk about other people's wants (たがる), and see 12 examples.
Hear it in a real conversation
See this pattern used naturally in a real-situation dialogue:
More N4 grammar to explore
Keep going with related patterns at the same level:
- 〜てしまう — 〜てしまう adds 'finish completely' or 'oops, ended up' to a verb. Learn the て-form formation, the regret nuance, past 〜てしまった, and the casual contractions 〜ちゃう / 〜じゃう.
- 〜間 — 〜間 means 'the whole time while' and pairs with a continuous action; 〜間に means 'at some point during.' Learn the formation, the key difference, and a clear minimal pair.
- 〜までに — 〜までに marks a deadline: do something by a time or event — 5時までに帰る ('be back by 5'). Learn the formation and how までに differs from まで ('until').
- Volitional Form — The plain volitional form means 'let's ~' or 'I'll ~'. Learn how to make 〜よう/〜おう from every verb type, how it relates to 〜ましょう, and what it builds toward.
- 〜ようと思う — 〜ようと思う uses the volitional form + と思う to say you've decided to do something: 勉強しようと思う. Learn the formation, the 〜ようと思っている variant, and how it differs from つもり and 予定.
- 謙譲語 — 謙譲語 (kenjougo) is humble Japanese: you lower yourself and your group to honor others. Learn the お〜する pattern and special humble verbs like 参る, いたす, 申す, and 伺う.