How to tell them apart
てある describes a state that already exists because someone did something earlier — the action is finished and you're observing the result, like 窓が開けてある. ておく focuses on the act of doing something now in preparation for later, like ビールを買っておいた. Swapping them is unnatural because てある won't convey the preparatory intent and ておく won't describe a visible resultant state.
- てある Use てある when you're describing a current state that results from a completed action.
- おく Use ておく when you do something now in preparation for a future need.
| Grammar point | Meaning | JLPT level |
|---|---|---|
| てある tearu | Something is in a completed or done state | N4 |
| おく oku | Carry out an action beforehand or leave it done | N4 |
てある tearu
Something is in a completed or done state
てある describes a thing left in a state after someone has acted on it on purpose, like a meal prepared in advance or a name written on a form. It follows the te-form of a transitive verb, as in 置いてある or 書いてあります, with the polite form using あります. It focuses on the visible result, not on who did the action, and it is different from ておく, which focuses on doing something in preparation.
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食事はオーブンのなかにおいてあります。
I have left you your dinner in the oven.
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車は用意してあります。
The car is ready.
おく oku
Carry out an action beforehand or leave it done
〜ておく means to do something in advance for future use or to leave something in a finished state. It is used for preparation, such as buying tickets early, or for leaving a door closed or a light on. It attaches to a verb in て, で, or ないで form, as in 買っておく, 飲んでおく, and 食べないでおく, and おく itself conjugates as an ordinary u verb. In casual speech ておく often contracts to とく, as in 買っとく.
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その魚は生かしておこう。
I will keep the fish alive.
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このサイトをブックマークしておいて。
Bookmark this site.
てある and おく are both JLPT N4 grammar points that Japanese learners often mix up. This page compares them side by side on meanings, usage and example sentences, so you can tell them apart.