How to say “I Know” in Japanese – Casual & Formal Ways

In this lesson, we learn how to say “I know” in Japanese. Like the English words “know” and “understand,” there are more than one words in Japanese to describe the situation that we are aware of something or what we comprehend.

Let’s find out the detailed meanings and correct usage of  “I know” in Japanese!

Japanese Words for “I Know”/ “I Understand”

There are different ways to express that you know something in the Japanese language. We’ve listed them down below.

Casual ways of saying “I Know” in Japanese

There are two verbs for the English expression “know” and “understand” in the Japanese language. Here are the detailed definitions and phrase examples.

• しる (Shiru | 知る | to know)
• わかる (Wakaru | 分かる、解る、判る | to know, to understand)

しる (Shiru | 知る)

Japanese people use the word しる (Shiru | 知る) when they know something. This expression is similar to “know” in English, though additional meanings can apply.

English Translation for しる (Shiru)

1. to acknowledge, to have knowledge
2. to notice, to sense
3. to grasp, to become conscious of
4. to be familiar with things, to remember something
5. to experience, to acquire
6. to learn, to get used to something
7. to get to know
8. to be responsible for something

Sentence Examples:

あのひとをしっています (Ano hito wo shitteimasu | あの人を知っています)

I know that person.

はじをしれ！ (Haji wo sire! | 恥を知れ！)

Shame on you!

それはわたしのしったことではない (Sore wa watashi no shitta koto de wa nai | それは私の知ったことではない)

That’s not my concern.

わかる (Wakaru | 分かる、判る、解る)

Japanese people use the word わかる (Wakaru | 分かる、判る、解る) in three different ways. It’s often written in ひらがな (Hiragana | 平仮名) and not in かんじ (Kanji | 漢字) because the meanings slightly differ in each form.

The Kanji 分かる is the most general form to use for “know” and “understand” in the Japanese language, and it can cover multiple circumstances. However, the other Kanji 解る and 判る are a little more specific.

When you comprehend something as a consequence of thinking logically, 解る is the correct expression. On the other hand, 判る is used for the situation after facts, meanings, and distinctions are clarified.

English Translation for わかる (Wakaru)

1. to distinguish, to understand
2. to become clear, to answer
3. to be sensible, have a keen insight
4. to get separated

Sentence Examples:

わたしはにほんごがわかりません (Watashi wa nihongo ga wakarimasen | 私は日本語が分かりません)

I don’t understand Japanese.

このじゅくごのいみはわかる？ (Kono jukugo no imi wa wakaru? | この熟語の意味は解る？)

Do you understand the meaning of this idiom?

ひがいしゃのみもとがわかったようです (Higaisha no mimoto ga wakattayou desu | 被害者の身元が判ったようです)

It seems that the victim has been identified.

Synonym and Related Verb

Below are different Japanese verbs that are synonymous with the verbs “to know” or “to understand” in Japanese.

If you’d like to learn more verbs in Japanese, you can refer to this article.

Formal ways of saying “I Know” in Japanese

The word しる (Shiru | 知る) and わかる (Wakaru | 分かる、判る、解る) could be inappropriate in certain formal situations. In those cases, the following words are preferred.

This change depends on the context and whom you’re talking to, so it would be complicated to study in a short time. Thus, we introduce you to the most common phrases here. Just remember, if a phrase finishes with ですます (Desu-Masu | ですます), it’s already good enough for casual conversations.

Japanese words for “I Know”/ “I Understand” in phrases

Now that you know the words used to express “I know” and “I understand” in Japanese, we’ll move on to the next level. Below are phrases that you can use for practice, categorized as positive, negative, and question phrases.

Positive Phrases

Here are the positive phrases that you can use related to saying “I know” in Japanese.

English	Kanji	Hiragana	Romaji
If there is anything you don't understand, please ask	分からないことがあったら聞いてください	わからないことがあったら、きいてください	Wakaranai koto ga attara, kiite kudasai
Really? I knew/heard it for the first time now	本当？今初めて知りました	ほんとう？いまはじめてしりました	Hontou? Ima hajimete shirimashita
There is no way I don't know it	僕が知らないわけがない	ぼくがしらないわけがない	Boku ga shiranai wake ga nai
I thought you knew it already	てっきり君は知っていると思っていた	てっきりきみはしっているとおもっていた	Tekkiri kimi wa shitteiru to omotteita
I'm sure you'll know when you grow up	大人になればきっと分かるよ	おとなになればきっとわかるよ	Otona ni nareba kitto wakaru yo
I became acquainted with a lot of people while traveling	旅行中にたくさんの人と知り合いました	りょこうちゅうにたくさんのひととしりあいました	Ryokouchuu ni takusan no hito to shiriaimashita
As far as I know, he is from the UK	私の知る限りでは、彼はイギリス出身です	わたしのしるかぎりでは、かれはいぎりすしゅっしんです	Watashi no shiru kagiri dewa, kare wa igirisu shusshin desu

Negative Phrases

Below you can find the negative phrases. These phrases relate to not understanding or knowing about the topic at hand.

Question Phrases

Lastly, here are also some phrases that you can use to ask questions related to “know” in Japanese.

To help you ask questions better, learning about the question words in Japanese can be very helpful.

Listening Tips

In Japanese, there are some words called いぬきことば (I-Nuki Kotoba | い抜き言葉 | words omitting “I” sound), and the change of sounds named おんびん (Onbin | 音便 | euphonic change). You might hear the following phrases regularly because it’s common in casual conversations.

*I-Nuki Kotoba

**I-Nuki Kotoba and colloquial expression

***Onbin

Wrap Up

That’s it for how to say “I know” and “I understand” in Japanese. Have some time for practice, and you’ll soon find yourself easily answering questions if you know about something!

Now on to the next word to learn! How about learning how to say “Don’t worry” in Japanese, next? Practice speaking Japanese every day and see the difference.