Today’s topic is the difference between 知らない (しらない;Shiranai) and わからない (Wakaranai). When they are translated literally, 知らない will be translated as “I don’t know” and わからない will be “I don’t understand”. But depending on the context, 知らない can be used as I don’t understand as well and vice versa. When to use 知らない and わからない is confusing to Japanese learners. So, let's check out the differences between 知らない and わからない in this article.
The difference between 知らない and わからない
知らない is used to express that the speaker doesn’t have knowledge about something, whereas わからない is used to express that the speaker cannot understand or has been taught something but he had forgotten.
Example of 知らない (しらない;shiranai)
この機械の使い方を知らない(このきかいのつかいかたをしらない/Kono Kikai no tsukaikata wo shiranai)
= I don’t know how to use this machine.
In this sentence, it shows that the speaker doesn’t know because one has no knowledge or information about the machine.
Example of わからない (wakaranai)
数学の問題がわからない(すうがくのもんだいがわからない/Sugaku no mondai ga wakaranai)
= I don’t understand this math problem.
In this sentence, it shows that one has not understood although it has been explained or taught.
The word 知らない has a strong meaning of "I don't have any information about this matter.” They are often used in questions that do not require thinking. わからない is often used when you can't find an answer to a question. And you can also use it with the meaning of "知らない.
When do you use it?
わからない is used when you answer “no” referring to yourself, 知らない is used when you answer “no” referring to someone else.
Example
Q. 夏休みはどこかいくの？(なつやすみはどこかいくの？/Natsu yasumi wa dokoka ikuno?
= Are you going anywhere during summer vacation?
A. まだわからない (Mada Wakaranai)
= I don’t know yet.
Q. お姉さんはどこへ行ったの？(おねえさんはどこへいったの？onee san ha dokohe ittano?)
= where did your sister go?
A. 知らない (しらない/shiranai)
= I don’t know.
In these two examples, both 知らない and わからない are translated as “I don’t know” but what is the difference? Think about it for a moment.
The point is that the first example is talking about yourself while the second example is about your sister. As such, use 知らない when you are talking about other people and use わからない when you are talking about yourself.
In addition, if you will be asked something using 知ってる？ (しってる？/Shitteru?) and you want to say “no”, 知らない is normally used, and if you will be asked something using わかる？(わかる？/Wakaru?) and you want to say “no”, わからない is more appropriate. Take a look at two examples.
Q. このお店知ってる？(このおみせしってる？/Kono omise shitteru?)
= do you know this shop?
A. ごめん、知らない (ごめん、しらない/Gomen, Shiranai)
= sorry I don’t know
Q.この問題の解き方わかる？(このもんだいのときかたわかる？/Kono mondai no tokikata wakaru?)
= do you know how to solve this question?
A. ごめん、わからない (ごめん、しらない/Gomen, Shiranai)
= sorry I don’t know
As shown above, if someone asks you a question with 知ってる？ and you want to answer “no”, you should answer using 知らない and if you are asked something using わかる？ and you want to say “no”, わからない is normally used.
Conclusion
To summarise, the difference between 知らない and わからない is whether you are talking about knowledge or understanding. If the subject of the sentence is you, then use わからない rather than 知らない, and if the subject is someone else, then use 知らない is more appropriate. Lastly, if the question is asked using 知ってる？ and if you want to say no, then simply use the same verb and answer with 知らない. If the question is asked with わかる？ and you want to say no, then わからない should be used. Both words have a very similar meaning but the slightest difference in nuance can give a different impression, so you have to be careful.
Momoka Yamaguchi