Video
Let’s watch this short video for a quick overview.
Source: gokigen japanese official YouTube Channel
Introduction
How to express that you have finished doing something / that something regrettable happens? The grammar pattern is “～てしまう.”
The grammar 〜てしまう has two main uses. First, it shows that you have completely finished an action. Second, it expresses that something happened unintentionally or with regret—“ended up doing…”.
Mastering this pattern will help you sound more natural and express both completion and feelings of “oops, that happened.”
1. Meaning & When to Use It
Meaning 1: Completion (finish doing something)
You do something completely, finish doing something, or have something done with determination.
Volitional verbs like する, 行く (which indicate that a person is willing to do something) are often used in this case.
Example:
- もう宿題をしてしまいました。= I’ve already finished my homework.
- 単語を覚えてしまいました。= I finished memorizing the words.
Meaning 2: Regret / Unintended action (end up doing)
Something regrettable happens beyond your control or intention.
Non-volitional verbs like natural or physiological phenomena (that are beyond human control) are often used in this case.
Example:
- 傘をなくしてしまいました。= I lost my umbrella (unfortunately).
- 風邪を引いてしまいました。= I caught a cold (too bad…).
- 転んでしまいました。= I accidentally fell down.
The Core Feeling: It’s Done and Can’t Be Undone
A helpful way to understand both meanings of ~te shimau is to think of “irreversibility.” The action is final.
- Completion: I finished the book (I can’t “un-finish” it).
- Regret: I lost my wallet (I can’t easily “un-lose” it).
This sense of finality is the core feeling that connects both uses.
How to Tell the Meanings Apart
Pro Tip: How to Know if it Means “Completion” or “Regret”
Context is key! Look for clue words in the sentence.
Usually signals COMPLETION: Adverbs emphasizing finality.
- もう (mou – already): もう宿題をしてしまいました。 (I’ve already finished my homework.)
- 全部 (zenbu – all): ケーキを全部食べてしまいました。 (I finished eating all the cake.)
Usually signals REGRET / UNINTENTIONAL: Adverbs expressing accident or carelessness.
うっかり(ukkari – carelessly): うっかり秘密を話してしまった。 (I carelessly ended up telling the secret.)つい(tsui – unintentionally): つい食べすぎてしまった。 (I unintentionally ended up eating too much.)
If there are no adverbs, the context of the situation (is it generally a good or bad outcome?) will tell you the nuance.
2. Structure & How to Form It
Take a verb in the て-form and add しまう.
- 読む → 読んで → 読んでしまう (to finish reading / end up reading)
- 飲む → 飲んで → 飲んでしまう (to finish drinking / end up drinking)
Tips: Casual speech 〜ちゃう (for てしまう) / 〜じゃう (for でしまう)
In casual / speech style, Vてしまう becomes Vちゃう（delete て) and Vでしまう becomes Vじゃう(deleteで).
Example:
階段でこけてしまいました。→ 階段でこけちゃいました。
Unfortunately, I tripped on the stairs.
もう今日の新聞を読んでしまいました。→ もう今日の新聞を読んじゃいました。
I’ve already read today’s newspaper.
3. Examples in Context
Completion
もう旅行の準備をしてしまいました。
I already finished preparing for the trip.
明日の朝早いので、もうお風呂に入ってしまいました。
Since I have to get up early tomorrow morning, I’ve already taken a bath.
夏休みが始まったばかりですが、もう宿題を終わらせてしまいました。
Summer vacation has just begun, but I’ve already finished my homework.
Regret / Unintended
駅で転んで、スマホを壊してしまいました。
I fell at the station and broke my smartphone.
昨日 夜ふかしをしたので、授業中に寝てしまいました。
I stayed up late last night, so I fell asleep during class.
ダイエット中なのに、おかしを食べすぎちゃいました。
I’m on a diet, but I ended up eating too many sweets.
4. Practice Time!
Try making your own sentences with 〜てしまう.
| Cue | Example Answer | English |
|---|---|---|
| 部屋をかたづける | 部屋をかたづけてしまいました。 | I cleaned up the room. |
| 財布を落とす | 財布を落としてしまいました。 | I dropped my wallet (by accident). |
| バナナを食べる | バナナを食べてしまいました。 | I ate the banana (finished it). |
Your turn: Make sentences with:
1) 本を読む
2) テストでミスをする
3) ジュースを飲む
FAQ
- QWhat’s the difference between simple past tense (〜ました) and 〜てしまいました?
- A
Simple Past (食べました): Neutral and factual. “I ate.”
〜てしまいました (食べてしまいました): Adds emphasis. It can mean either:
- Completion: “I finished eating it all.” (Emphasizes the completeness of the action).
- Regret/Unintentional: “Oops, I ate it.” (When you maybe shouldn’t have).
Use 〜てしまう when you want to add that extra layer of meaning about finality or feeling.
- QHow do I know when to use 〜ちゃう and 〜じゃう?
- A
〜ちゃう (chau): Use for verbs whose te-form ends in 〜て (e.g., 見て → 見ちゃう, 行って → 行っちゃう).
〜じゃう (jau): Use for verbs whose te-form ends in 〜で (e.g., 読んで → 読んじゃう, 飲んで → 飲んじゃう).
Remember, these are casual forms for spoken Japanese with friends and family. Stick to 〜てしまう in polite or formal situations.
- QCan 〜てしまう be used for positive things?
- A
Yes. While one main meaning is “regret,” the “completion” meaning is often positive or neutral. It can show a sense of accomplishment. Furthermore, the “unintentional” meaning can be used for surprising but good outcomes.
Example: この本は面白すぎて、一日で読んでしまいました。 (This book was so interesting, I ended up reading it all in one day!) → This expresses surprise and absorption, not regret.
Conclusion
Now you know how to use 〜てしまう in two ways: to show something is completely finished, and to express that something happened unintentionally.
Use the polite 〜てしまいました in lessons or formal contexts, and the casual 〜ちゃった / 〜じゃった when chatting with friends. Practice often—you’ll naturally develop a sense of whether it sounds like “finished it” or “oops, ended up doing it.”
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