Dictionary / Japanese / I don't know
How to Say "I don't know" in Japanese
わかりません
wakarimasen
Literally: It is not clear to me
わかり
understand, be clear
ません
(polite negative)
Polite or casual
Politeわかりません
Casualわからない (wakaranai)
わかりません is polite and works with teachers, staff and strangers. It covers both "I don't know" and "I don't understand". Put すみません、ちょっと (sumimasen, chotto) in front to make it softer. With friends, say わからない, or more casually わかんない (wakannai).
Correct
わかりません
What people say wrong
知りません
I don't know. Correct, but as an answer it can sound curt, like "no idea, not my business".
The mistake to avoid. English uses "I don't know" for almost everything, so learners reach for 知りません (shirimasen), from 知る, to know. As an answer to a question, it can sound cold, as if the matter has nothing to do with you. わかりません is softer and is what most people say when they cannot answer. 知りません is fine for plain facts, such as not knowing a person or a place.
In context
すみません、ちょっとわかりません。
Sumimasen, chotto wakarimasen.
Sorry, I'm not sure.
日本語がよくわかりません。
Nihongo ga yoku wakarimasen.
I don't understand Japanese very well.
まだわからない。
Mada wakaranai.
I don't know yet. (casual)