How do you say “Of course!” in Japanese?

You might already know もちろん, but Japanese has several other expressions you can use depending on the situation.

In this blog, we’ll learn four useful expressions: もちろん, いいですよ, 当然（とうぜん）, and 当たり前（あたりまえ）. Although they can sometimes have similar meanings, they are used in different situations!

1. もちろん – Of Course! / Sure!

Meaning: Of course! / Certainly! / Sure!

もちろん is a common expression used when agreeing to a request or confidently saying yes. It works in many everyday situations and can sound friendly and natural.

When to use it

• When agreeing to help someone
• When confirming something enthusiastically
• When saying that something is obvious to you

Example conversation

A: 手伝てつだってくれる？
Can you help me?

B: もちろん！
Of course!

Another example

A: 日本語にほんごが好すきですか？
Do you like Japanese?

B: もちろん！
Of course!

💡 Tip: もちろん can be used on its own or at the beginning of a sentence. It is versatile, but the appropriate level of politeness depends on the situation.

2. いいですよ – Sure! / That’s Fine!

Meaning: Sure! / That’s fine! / You may!

いいですよ is a polite expression used to agree to a request, give permission, or tell someone that something is okay.

Unlike もちろん, which emphasizes “of course,” いいですよ focuses more on giving approval or saying that something is acceptable.

When to use it

• When giving someone permission
• When agreeing to a request
• When telling someone that something is okay

Example conversation

A: ここに座すわってもいいですか？
May I sit here?

B: いいですよ。
Sure! / Yes, you may.

Another example

A: 明日あした、来きてもいいですか？
May I come tomorrow?

B: いいですよ。
Sure, that’s fine.

💡 Tip: いいですよ is polite and useful in everyday conversations. However, depending on your tone, it can sometimes sound like you are granting permission rather than simply agreeing.

3. 当然とうぜん – Naturally / As Expected

Meaning: Naturally / Of course / As expected

当然（とうぜん） expresses that something is expected, reasonable, or only natural given the circumstances.

It often emphasizes what should logically happen rather than simply agreeing to a request.

When to use it

• When something is expected
• When something seems reasonable or logical
• When emphasizing that something is only natural

Example conversation

A: 毎日練習まいにちれんしゅうしたら、上手じょうずになるよね？
If you practice every day, you’ll improve, right?

B: 当然とうぜんだよ！
Of course! / Naturally!

Another example

約束やくそくを守まもるのは当然とうぜんです。

Keeping your promises is only natural.

💡 Tip: 当然（とうぜん） can sound firm or assertive, especially when used as a standalone response. It is not always the best choice when you simply want to say “Sure!” to a friend.

4. 当あたり前まえ – Obviously! / Goes Without Saying!

Meaning: Obviously / Of course / It’s only natural

当たり前（あたりまえ） describes something that is obvious, normal, or expected. In casual conversation, 当たり前（あたりまえ）！ can express a strong sense that something goes without saying.

When to use it

• When something seems obvious
• When expressing that something should be expected
• When emphasizing that something is only natural

Example conversation

A: 困こまっている友達ともだちを助たすける？
Would you help a friend who’s in trouble?

B: 当あたり前まえ！
Of course! / Obviously!

Another example

毎日まいにちあいさつをするのは当あたり前まえです。

Greeting people every day is a normal thing to do.

💡 Tip: 当たり前（あたりまえ） can sound strong or even a little rude if you use it in the wrong context. When talking to friends, it can express confidence or enthusiasm, but in polite situations, choose your words carefully.

What’s the Difference?

Expression	Meaning	Best situation
もちろん	Of course! / Sure!	Agreeing enthusiastically
いいですよ	Sure! / That’s fine!	Giving permission or accepting a request
当然（とうぜん）	Naturally / As expected	Expressing what is expected or logical
当たり前（あたりまえ）	Obviously / Goes without saying	Emphasizing what should be obvious

Final Thoughts

Although these four expressions can all relate to the idea of “of course,” they aren’t interchangeable in every situation.

• もちろん！ — Of course! I’m happy to!
• いいですよ。 — Sure! That’s fine!
• 当然とうぜん！ — Naturally! That’s what you’d expect!
• 当あたり前まえ！ — Obviously! It goes without saying!

Start by practicing もちろん and いいですよ, as they are especially useful in everyday conversations. As you become more comfortable with Japanese, try using 当然（とうぜん） and 当たり前（あたりまえ） when the context fits.

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