はずがないCannot reasonably be expected
はずがない says that something cannot reasonably be true or happen because it conflicts with known facts, a schedule, a rule, or another clear basis for expectation.
Rejecting an expectation
First identify what the available facts would lead you to expect. Then use はずがない to reject a possibility that does not fit those facts. The reason may be stated in the same sentence or already clear from the situation.
最終便はもう出ましたから、今から乗れるはずがありません。
The last service has already left, so there is no way to board it now.
AnalyzeThe departure schedule supplies the reason for rejecting the possibility.
Present, past, and future situations
The clause before はずがない identifies the event or state being rejected. That event can belong to the present, past, or future. The surrounding facts and the form of the verb make the time clear.
Reasoning across time
まだ一度も会っていないのだから、彼が私の顔を知っているはずがない。
We have never met, so there is no way he knows my face.
Analyze入館記録がないので、彼が昨夜ここに来たはずがない。
There is no entry record, so he cannot have come here last night.
Analyzeこの列車は空港まで直通だから、途中で乗り換えるはずがない。
This train goes directly to the airport, so there should be no need to transfer on the way.
AnalyzeNearby forms
はずだ accepts the expectation supported by the facts, while はずがない rejects it. わけがない often sounds more like a categorical or subjective dismissal, though real usage overlaps and context matters. っこない is markedly more casual and forceful.
More examples
明日は店の定休日だから、開いているはずがない。
Tomorrow is the shop’s regular closing day, so it cannot be open.
Analyzeこのかばんは空だから、重いはずがない。
This bag is empty, so it cannot be heavy.
Analyze隣で工事をしているのだから、この部屋が静かなはずがない。
Construction is going on next door, so this room cannot be quiet.
Analyze名札には「研修生」と書いてある。彼が責任者のはずがない。
His name tag says “trainee.” He cannot be the person in charge.
Analyze鍵は私が持っていたので、誰も部屋に入れるはずがなかった。
I had the key, so no one could reasonably have been able to enter the room.
Analyze申込書は昨日発送したので、今日届くはずがありません。
The application was sent yesterday, so it cannot be expected to arrive today.
Analyze