🇯🇵 Japanese phrases

How to Say "I don't know" in Japanese

The SPAIKING TeamJuly 27, 2026
わからない
"I don't know" in Japanese · say it like wah-kah-rah-nai

The most natural way to say "I don't know" in Japanese is わからない. Tap the speaker above to hear it, then say it back out loud. That is the fastest way to make it stick.

Other ways to say it

分からない
This is a more formal way to say it.
知らない
Use this when you mean 'I don't know' in a more casual context.

When to use it

You can use this phrase when you genuinely do not have the information someone is asking for. It is appropriate in both casual and formal situations. If you want to express uncertainty, this is a good phrase to use.

Say it out loud, get corrected

Reading it is not the same as saying it. Practice "I don't know" and thousands more with an AI coach that listens.

Examples in Japanese

JapaneseEnglish
その問題についてはわからない。I don't know about that problem.
彼のことは知らない。I don't know him.
Common mistake
Some learners may confuse this with 'わかる' (to understand) and forget to negate it.

The fastest way to remember it

Vocabulary you only read fades fast. Vocabulary you say out loud sticks. Hear わからない, repeat it a few times, then use it in a real sentence. SPAIKING lets you practice exactly that, speaking Japanese with a coach that corrects your pronunciation in real time. You can start with two free conversations.

Frequently asked questions

Can I use this phrase in a formal meeting?

Yes, it is appropriate to use in formal settings as well.

Learn Japanese by speaking it

Two free conversations. No card needed.