Translation guide
Expresses that something is obvious, expected, or naturally true. In Japanese, the best choice depends on whether you are giving permission, stating a fact, or responding to thanks.
The speaker is allowing someone to do something or agreeing to a request, similar to 'sure' or 'go ahead'.
The most common and neutral way to say 'of course' when giving permission or agreeing. Can be used in both casual and polite situations.
「この本、借りてもいい？」「もちろん。」
"Can I borrow this book?" "Of course."
A friendly, slightly softer way to grant permission. More conversational than もちろん.
「窓を開けてもいいですか？」「いいですよ。」
"May I open the window?" "Of course."
Used when offering something or inviting someone to do something. Equivalent to 'please, go ahead'.
「お手洗いをお借りしてもいいですか？」「どうぞ。」
"May I use your restroom?" "Of course."
The speaker is emphasizing that a fact is clearly true or should be known to the listener.
Works for both obvious facts and personal assertions. Can be used before or after the statement.
彼はもちろん来るよ。
Of course he's coming.
もちろん、私は賛成です。
Of course I agree.
Stronger and more blunt than もちろん. Often used when the speaker thinks the answer is extremely obvious. Can sound rude if used inappropriately.
Can sound arrogant or dismissive. Use only with close friends or in informal situations.
「宿題やった？」「当たり前だろ。」
"Did you do your homework?" "Of course."
Similar to 当たり前 but slightly more formal and logical. Implies that something is a natural consequence.
彼が怒るのは当然だ。
It's only natural that he's angry.
The speaker is downplaying the favor or help they gave, similar to 'you're welcome' or 'no problem'.
A warm and natural response to thanks among friends or in casual settings. Implies 'of course I would do that for you'.
「手伝ってくれてありがとう。」「もちろん！」
"Thanks for helping me." "Of course!"
A humble, casual way to say 'not at all' or 'no problem'. Often used when the favor was small.
The speaker acknowledges a point but adds a reservation, similar to 'of course, but...'.
Used to concede a point before introducing a contrasting idea. The が means 'but'.
もちろん彼は優秀だが、経験が足りない。
Of course he's talented, but he lacks experience.
Literally 'certainly... but'. A slightly more formal alternative to もちろん〜が.
確かに便利だが、値段が高い。
Of course it's convenient, but it's expensive.
All three can translate 'of course', but they differ in nuance. もちろん is the safest and most versatile. 当たり前 is casual and can sound blunt ('obviously!'). 当然 is more logical and formal ('naturally'). Use もちろん unless you want to emphasize strong obviousness or logical consequence.
もちろん手伝うよ。
Of course I'll help. (neutral)
手伝うのは当たり前だ。
It's obvious I'll help. (strong, casual)
手伝うのは当然です。
It's only natural that I help. (logical, formal)
In English, 'of course' is used very frequently. In Japanese, using もちろん too often can sound repetitive or overly emphatic. In many cases, a simple はい or ええ is more natural, especially when simply agreeing.
「明日来ますか？」「はい、行きます。」
"Will you come tomorrow?" "Yes, I will." (not 'Of course I will')
The standard polite 'you're welcome'. Slightly more formal than もちろん in this context.
「ありがとうございます。」「どういたしまして。」
"Thank you very much." "You're welcome."
「ありがとう！」「いえいえ。」
"Thanks!" "No problem."