Meaning & Usage
✨ Basic Meaning
“It must be…”, “It is expected that…”, “It should be…”
🎯 Primary Function
To express a speaker’s high conviction or certainty about a situation, relying on objective evidence, logic, or prior knowledge.
📋 Grammar Structure
Verb (Plain form: Vる, Vた, Vない) + はずだ
い-Adjective + はずだ
な-Adjective + な + はずだ
Plain Negative Form + はずだ / はずがない
🎭 Usage Contexts
Formal Situations
Used with です/ます forms (はずです) to maintain politeness, often in business meetings or formal discussions to confirm plans.
Informal Situations
Used casually with だ (はずだ) among friends or family when expressing personal certainty.
Written Language
Common in essays, reports, or articles to draw a logical conclusion or state a widely accepted expectation.
Spoken Language
Extremely common. Often accompanied by upward intonation at the end when expressing surprise that the expectation wasn’t met.
💡 Common Applications
Expressing Strong Expectation Based on Logic/Evidence
Used to state a high probability or certainty based on a known fact or logical deduction. This is the primary use.
Example: 彼は日本語を五年勉強したから、話せるはずだ。 (Kare wa Nihongo o gonen benkyō shita kara, hanaseru hazu da.)
Stating a Predetermined Schedule or Plan
Used to confirm what is expected according to a schedule, promise, or rule. It often implies a slight surprise or concern if the event doesn’t happen.
Example: 会議は午後３時に始まるはずです。 (Kaigi wa gogo san-ji ni hajimaru hazu desu.)
Expressing Strong Denial (はずがない)
When used in the negative form (はずがない), it means “It cannot possibly be,” expressing a confident denial based on one’s reasoning.
Example: そんな難しいテストに合格したはずがない。 (Sonna muzukashii tesuto ni gōkaku shita hazu ga nai.)
Frequency
High
Difficulty
N4 / N3 Intermediate
Tag:
Example Sentences
Example #1
彼女は昨日出発したから、今日着くはずだ。
Furigana: かのじょは きのう しゅっぱつしたから、きょう つく はずだ。
Romaji: Kanojo wa kinō shuppatsu shita kara, kyō tsuku hazu da.
English: She left yesterday, so she should arrive today.
Example #2
この問題は簡単だから、誰でもわかるはずだ。
Furigana: この もんだいは かんたんだから、だれでも わかる はずだ。
Romaji: Kono mondai wa kantan da kara, dare demo wakaru hazu da.
English: This problem is easy, so anyone should understand it.
Example #3
田中さんは真面目なはずなのに、今日は遅刻した。
Furigana: たなかさんは まじめな はずなのに、きょうは ちこくした。
Romaji: Tanaka-san wa majime na hazu na noni, kyō wa chikoku shita.
English: Mr. Tanaka is supposed to be serious, but he was late today.
Example #4
鍵は机の上にあったはずだけど、見当たらない。
Furigana: かぎは つくえの うえに あった はずだけど、みあたらない。
Romaji: Kagi wa tsukue no ue ni atta hazu dakedo, miataranai.
English: The key should have been on the desk, but I can’t find it.
Example #5
電車はもう出たはずがない。まだ時間がある。
Furigana: でんしゃは もう でた はずがない。まだ じかんがある。
Romaji: Densha wa mō deta hazu ga nai. Mada jikan ga aru.
English: The train cannot possibly have left yet. There is still time.
Example #6
彼の話は本当のはずがない。
Furigana: かれの はなしは ほんとうの はずがない。
Romaji: Kare no hanashi wa hontō no hazu ga nai.
English: His story cannot be true.
Example #7
新しいシステムは来週導入されるはずだ。
Furigana: あたらしい システムは らいしゅう どうにゅうされる はずだ。
Romaji: Atarashii shisutemu wa raishū dōnyū sareru hazu da.
English: The new system is expected to be introduced next week.
Example #8
こんなに勉強したのだから、合格するはずだ。
Furigana: こんなに べんきょうしたのだから、ごうかくする はずだ。
Romaji: Konna ni benkyō shita no da kara, gōkaku suru hazu da.
English: Since I studied this much, I must pass (the exam).
Example #9
今日は休みのはずだから、彼に電話するのはやめておこう。
Furigana: きょうは やすみの はずだから、かれに でんわするのは やめておこう。
Romaji: Kyō wa yasumi no hazu da kara, kare ni denwa suru no wa yamete okō.
English: Since today is supposed to be his day off, let’s refrain from calling him.
Example #10
このレストランは美味しいはずだよ。ネットで評判だったから。
Furigana: この レストランは おいしい はずだよ。ネットで ひょうばんだったから。
Romaji: Kono resutoran wa oishii hazu da yo. Netto de hyōban datta kara.
English: This restaurant must be delicious. It had a good reputation online.
Notes & Nuances
📌 Important Points
Implied Contradiction or Surprise
Hazu da often implies that the speaker has some evidence for their belief, and if the expectation is not met (as in the example), it conveys surprise or slight confusion.
Example: 電車は来るはずなのに、まだ来ない。 (Densha wa kuru hazu na noni, mada konai.)
Reference to Past Expectations
When used with the past tense (Vた), it refers to a strong conviction about a past state or event (“It should have been…”). This is common when searching for something.
Example: 鍵は机の上にあったはずだ。 (Kagi wa tsukue no ue ni atta hazu da.)
Noun Modification Rule (の)
When modifying a Noun, ‘の’ is essential (Noun + の + はずだ). This structure treats はず as a quasi-noun.
Example: 彼は先生のはずだ。 (Kare wa sensei no hazu da.)
⚠️ Common Mistakes
❌ 使いますはずだ (Tsukaimasu hazu da)
✅ 使っているはずだ (Tsukatte iru hazu da)
‘Hazu da’ attaches to the plain form of the verb, including the progressive ‘ている’ form. Do not use the V-masu stem.
❌ 本当はずだ (Hontō hazu da)
✅ 本当のはずだ (Hontō no hazu da)
Nouns require the particle ‘の’ when modifying ‘はず’. Failing to include ‘の’ is a common structural error.
❌ 美味しいはずだよ (when only guessing)
✅ それは良いはずだ (Sore wa ii hazu da)
‘Hazu da’ expresses an expected reality. While it can attach to adjectives, using it for simple subjective opinions (like ‘should be good’) can sound overly assertive compared to a softer conjecture like ‘だろう’. Use when there is an objective reason for the goodness.
🏛️ Cultural Context
Politeness Level: Neutral to Polite (はずです) or Plain (はずだ). It is generally acceptable in most social settings.
Social Situations: Frequently used when explaining the reason for something, apologizing for a mistake (“I was supposed to be here”), or expressing confidence in an outcome.
Regional Variations: Standard across Japan. The use of ‘はず’ is consistent.
🔍 Subtle Differences
はずだ vs. だろう
はずだ expresses high certainty based on concrete evidence or logic. だろう expresses a simple conjecture or guess (lower certainty).
When to use: Use はずだ when you have a verifiable reason (e.g., a schedule, observation, or law). Use だろう when merely guessing.
はずだ vs. に違いない
はずだ is logical and objective (based on rules/evidence). に違いない (ni chigai nai) is more subjective and forceful, meaning “It must be” or “No doubt.”
When to use: Use はずだ for expected outcomes; use に違いない when you feel a strong, almost emotional certainty about something.
はずだ vs. べきだ
はずだ states what IS expected to happen (reality/probability). べきだ states what OUGHT to happen (obligation/duty).
When to use: Use はずだ to talk about what *will* happen; use べきだ to talk about what *should* be done.
📝 Conjugation Notes
The grammar pattern はずだ always follows the Plain Form (dictionary form) of the preceding word, which acts as a noun modifier (similar to how Noun + の + Noun works). The final ‘だ’ can be replaced by ‘です’ for politeness.
🔊 Pronunciation Tips
Pronounce はず (hazu) with a flat pitch. The emphasis usually falls on the evidence or reason stated before the grammar point.
🧠 Memory Tips
Think of はず (hazu) as “the expectation” or “the natural outcome.” The pattern establishes a logical link: [Reason] + [Plain Form] + はずだ = The logical outcome is [X].
Other Grammar
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