Which one should you use?
While もちろん expresses enthusiastic agreement, 当たり前 often carries the nuance that something is a matter of course, obvious or expected, sometimes even with a slightly dismissive or critical undertone. 当たり前 specifically means 'natural', 'obvious' or 'taken for granted'.
Is there a formal and an informal way to say it?
Using it alone to answer a question can sound somewhat blunt or casual. To adjust the tone, you can add particles like さ or よ. For a more formal approach, 当然 is a polite way to convey 'of course', suggesting the statement is expected or obvious, while 確かに can be used in formal discussions to mean 'certainly' or 'indeed' to emphasize agreement.
Related words
How does it change in a sentence?
To make the enthusiastic agreement polite, you should follow the phrase with a polite verb or copula, such as もちろん〜です.
How do you pronounce it?
mochiron
Did you know?
- The phrase もちろん can be written using the kanji 勿論, where the first character means 'do not' and the second means 'discuss'. It literally implies that a point is so obvious it does not even need to be discussed.
- In highly formal settings, Japanese speakers often avoid もちろん and instead use 承知いたしました to signify they have understood and accepted a request.
- Adding the particle さ to もちろん creates a tone of confidence or lightheartedness that can make the speaker sound like a 'cool' or assertive character in anime.
Examples in context
- もちろんさ。Of course.This sentence is useful for a simple 'of course' using もちろんさ.Tatoeba #193379 by bunbuku, translation #433492 by CK
- もちろんいいとも。Of course, you may.This sentence shows how to say 'of course, you may' using もちろん.Tatoeba #193380 by small_snow, translation #30544 by Mediabat
- もちろん、行くよ。Of course I will go.This sentence demonstrates using the phrase to say 'of course I will go' with もちろん.Tatoeba #9795383 by small_snow, translation #30533 by CC
- ご質問があれば、遠慮なくどうぞ。もちろんお答えいたします。If you have any questions, please feel free to ask. I will, of course, answer them.
- 「明日遊びに行こうよ。」「もちろん、行こう！」"Let's go have fun tomorrow." "Of course, let's go!"
- 75 more sentences on Tatoeba
Example conversation
A student asks a friend if she can join their study group.
- 美咲 Misaki一緒に勉強してもいい？Issho ni benkyou shite mo ii?Can I study with you?
- 陽太 Yotaもちろん、いいよ！Mochiron, ii yo!Of course, you can!
- 美咲 Misakiありがとう、助かる！Arigatou, tasukaru!Thank you, that helps a lot!
- 陽太 Yota一緒に頑張ろうね。Issho ni ganbarou ne.Let's do our best together.
Sources
- Pronunciation: Wiktionary entry もちろん, CC BY-SA 4.0, dump of 2026-09-26.
- Example sentences: Tatoeba CC BY 2.0 FR.
