Meaning
The speaker completely rules out a possibility: "there's no way", "it can't be that…". It rests on common sense or knowledge of the situation and sounds emotional and firm. わけはない means the same with extra stress from は.
Formation
- V普通形＋わけがない: できる → できるわけがない, 見た → 見たわけがない
- Vない＋わけがない (double negative = "definitely"): 知らない → 知らないわけがない
- Aい＋わけがない: 安い → 安いわけがない
- Aな＋わけがない: 簡単だ → 簡単なわけがない
- N + な / の / である + わけがない: 本物なわけがない / 本物のわけがない / 本物であるわけがない
- Variants: わけはない; casual わけない; polite わけがありません
When to use it
- Where to use it
- In arguments, when indignant, or when firmly denying something: あの真面目な人がうそをつくわけがない "Someone that honest would never lie."
- Where not to use it
- Not for a partial denial ("it's not that…") — that is わけではない. And not for "I can't allow myself to" — that is わけにはいかない.
Examples
20 sentences-
あんなに優しい彼がそんなことを言うわけがない。
Someone as kind as him would never say something like that.
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駅から近くてこんなに広い部屋が、安いわけがありません。
A room this big and this close to the station can't possibly be cheap.
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毎日十二時間も働いて、体が平気なわけがない。
Working twelve hours a day, every day — there's no way your body is fine with that.
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こんなに安いバッグが本物なわけがないよ。
A bag this cheap can't possibly be genuine.
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現場にいなかった彼が、犯人であるわけがない。
He wasn't even at the scene — he can't possibly be the culprit.
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三歳の娘がこの重い箱を開けたわけがない。
There's no way my three-year-old daughter opened this heavy box.
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ちゃんと準備したんだから、失敗するわけはない。
We prepared properly, so there's no way we'll fail.
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こんな難しい問題、子どもに解けるわけないでしょ？
There's no way a kid could solve a problem this hard, come on!
12 more examples
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同じクラスなんだから、名前を知らないわけがない。
We're in the same class — there's no way he doesn't know my name.
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そんなに簡単に日本語が上手になるわけがありません。
There's no way anyone gets good at Japanese that easily.
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一度聞いただけで、全部覚えられるわけがない。
There's no way you can remember everything after hearing it just once.
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あの真面目な田中さんが、会議を忘れたわけがない。
There's no way someone as conscientious as Tanaka forgot the meeting.
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甘い物が大好きな妹が、このケーキを食べないわけがない。
My sister loves sweets — there's no way she won't eat this cake.
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有名なシェフの店ですから、まずいわけがありません。
It's a famous chef's restaurant, so there's no way the food is bad.
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初めての一人暮らしが、楽なわけがないよ。
Living alone for the first time can't possibly be easy.
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まだ二十歳の彼が、社長のわけがない。
He's only twenty — there's no way he's the company president.
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道は一本しかないから、迷うわけはない。
There's only one road, so there's no way you'll get lost.
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三日で十キロもやせるわけないでしょ？
There's no way you can lose ten kilos in three days, right?
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さっき出たばかりだから、もう着いているわけがない。
He only just left, so there's no way he's there already.
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新人の私に、そんな大きな仕事ができるわけがありません。
I'm new here — there's no way I could handle such a big job.
Important notes
- Very close to はずがない; わけがない tends to sound more emotional and colloquial, はずがない more like a conclusion from known facts.
- Casual versions are わけない, わけないでしょ／じゃない; in polite speech use わけがありません.
Common mistakes
- ✗ 彼が犯人わけがない → ✓ 彼が犯人なわけがない / 犯人のわけがない / 犯人であるわけがない — a linking form is required between N and わけ.
- ✗ この問題が簡単わけがない → ✓ この問題が簡単なわけがない — a na-adjective keeps な.
- ✗ 高いからおいしいわけがない (meaning "expensive doesn't mean tasty") → ✓ 高いからおいしいわけではない — わけがない is a total denial; "it doesn't follow that" is わけではない.
Check yourself
Pick the translation of each sentence. The wrong options translate similar patterns, so watch the grammar rather than the words.
Similar grammar
- 〜はずがないはずがない is "can't be" as a conclusion from facts and logic; わけがない says the same more emotionally, from common sense. They are often interchangeable.
- 〜わけではないわけではない is a partial denial ("it's not that…", "it doesn't mean…"); わけがない is a total "no way".
- ～わけにはいかないわけにはいかない is "I can't allow myself to" (the speaker's own decision); わけがない judges likelihood: "there's no way".
- ～わけだわけだ ("so that's why", "in other words") confirms a conclusion; わけがない rules it out.
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