はずだExpected to; should be
はずだ expresses a strong expectation or reasoned conclusion based on knowledge, experience, a schedule, a rule, or the circumstances. It means that something should be true if the speaker's information is correct.
Start from a basis
はずだ is stronger than simply saying that something may happen. The speaker has a reason for the expectation and treats the result as what should logically follow. That reason may be stated in the sentence or already understood from the situation.
時刻表では、電車は十時に着くはずです。
According to the timetable, the train should arrive at ten.
AnalyzeDifferent words before the expression
The form immediately before the expression changes according to whether it is a verb, adjective, or noun.
田中さんは昨日送ったと言っていたので、メールはもう届いたはずだ。
Tanaka said yesterday that it had been sent, so the email should have arrived by now.
Analyze今日は日曜日だから、あの店は開いていないはずです。
Today is Sunday, so that shop should not be open.
Analyzeこの部屋は防音だから、静かなはずだ。
This room is soundproof, so it should be quiet.
Analyze予約表によると、次の担当者は佐藤さんのはずです。
According to the booking sheet, the next person in charge should be Sato.
AnalyzeWhen reality does not match
彼はもう駅に着いているはずなのに、まだ連絡がない。
He should already be at the station, but I still have not heard from him.
AnalyzeThe missing message conflicts with the speaker's expectation, creating a puzzled or concerned tone.
Expectation versus other strong conclusions
はずだ presents something as expected because of knowledge, assumptions, or circumstances. わけだ instead presents an understanding or conclusion drawn from facts that have already been established. に違いない emphasizes the speaker's strong conviction, while はずだ draws attention to the basis that makes the result expected.
More examples
地図が正しければ、郵便局はこの角を曲がったところにあるはずです。
If the map is correct, the post office should be just around this corner.
Analyze鍵は机の上に置いたから、そこにあるはずだ。
I put the key on the desk, so it should be there.
Analyzeこのパソコンは先週買ったばかりだから、まだ新しいはずです。
This computer was bought only last week, so it should still be new.
Analyze受付で確認したので、予約は入っているはずです。
I checked at reception, so the reservation should be in the system.
Analyze昨日は祝日だったから、銀行は閉まっていたはずだ。
Yesterday was a public holiday, so the bank should have been closed.
Analyze説明書によれば、このボタンを押せば前の画面に戻るはずです。
According to the instructions, pressing this button should return you to the previous screen.
Analyzeこの道は工事中だから、今日はバスが通らないはずだ。
This road is under construction, so buses should not come through today.
Analyze