When something is completely obvious or goes without saying, Japanese speakers reach for 当然 or 当たり前. Both mean “of course” or “naturally”, but they are not interchangeable — and mixing them up is a very common mistake among learners. This guide will make the distinction crystal clear.
Yuka当然 と 当たり前 ってどう違うの？ (What’s the difference between touzen and atarimae?)
Rei当然 は少し改まった言い方で、副詞・名詞・形容詞として使えるよ。当たり前 はもっと日常的な表現で、副詞としては使えないんだ。 (Touzen is slightly more formal and can act as an adverb, noun, or adjective. Atarimae is more everyday and cannot be used as an adverb.)
At a Glance
| Word | Reading | Register | Parts of Speech | Key Nuance |
|---|---|---|---|---|
| 当然 | touzen | Slightly formal | Adverb, Noun, Adjective | Stronger and more assertive; can be used as a standalone adverb |
| 当たり前 | atarimae | Everyday / Casual | Noun, Adjective (NOT adverb) | More neutral; cannot stand alone before a verb as an adverb |
当然 (touzen) — “Of Course / Definitely / That’s Totally Obvious”
“当然” can function as an adverb (before a verb), a noun, or an adjective. It sounds more formal and carries a slightly stronger, more assertive tone than 当たり前.
当然、私は怒る。 (I will definitely get angry.) — correct as adverb
当然だよ！ (That’s totally obvious!) — used as noun/predicate
Sample Conversation
Rei今回、お前が練習をさぼっていたから日本代表に選ばれなかったんだよ！当然だよ！ (You’ve been skipping practice, so you weren’t chosen for the national team. That’s only natural!)
Yukaまた、０点とってしまった・・・当然、お母さん怒るだろーな。 (I got a zero again… Mum will definitely be mad.) (mata, 0-ten totte shimatta… touzen, okaasan okoru darō na.)
Rei道で拾った財布は交番に届けろよ！当然だろ！ (Turn in a wallet you found on the street to the police box! That’s totally obvious!) (touzen darō!)
当たり前 (atarimae) — “Naturally / That’s Obvious / Common Sense”
“当たり前” is used in a similar way to 当然, but it cannot be used as a standalone adverb before a verb. If you want to use it in that structure, you need to rephrase:
Wrong: 当たり前、私は怒る。
Correct: 私が怒るのは当たり前だ。 (It is only natural that I get angry.)
Sample Conversation
Reiえっ？ラーメンとごはんの組み合わせ？俺の実家なら当たり前だけどー・・・ (What? Ramen with rice? That’s perfectly normal in my family home…)
Yuka試験前なのに当たり前のように毎日１２時間くらい寝てるよね？試験、大丈夫なの？ (You’re sleeping about 12 hours every day as if it’s normal, even before exams. Are you okay?) (atarimae no you ni mainichi jūni jikan kurai ne teru yo ne?)
Yukaいやいや、二日前は一昨日って当たり前じゃね？ (Come on, isn’t it obvious that 2 days ago is the day before yesterday?) (atarimae jya ne?)
Quick Quiz
Choose 当然 or 当たり前 (or both) for each blank.
Q1. _____ 、彼は怒った。(He was _____ angry.) → Answer: 当然 only (adverb position — 当たり前 cannot be used here)
Q2. 彼が怒るのは _____ だ。(It is _____ that he got angry.) → Answer: Both 当然 and 当たり前 work here
Q3. ルールを守るのは _____ のことだ。(Following the rules is _____.) → Answer: 当たり前 (most natural in this common set phrase)
当然 and 当たり前 both convey “of course / naturally”, but 当然 is slightly more formal and can function as an adverb before a verb, while 当たり前 is more conversational and cannot. When in doubt in a formal or written setting, 当然 is the safer choice.
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