Wakarimasen and shirimasen: the two main verbs
分かりません (wakarimasen) comes from wakaru, to understand or be able to tell. Saying wakarimasen means "I can't tell", "I'm not sure" or "I don't understand". It suggests you have thought about it and cannot reach an answer.
知りません (shirimasen) comes from shiru, to know or come to know. It means "I have no information about it". That is perfectly correct for facts you never learned, but it can sound like the end of the conversation. Our guide to wakaru and shiru covers the grammar in detail; here we focus on how each one lands in real conversation.
| Phrase | Core meaning | How it can sound |
|---|---|---|
| 分かりません | I can't tell or don't understand | Neutral, cooperative |
| 知りません | I have no information | Correct but can sound cold |
| ちょっと分からないです | I'm not really sure | Soft, polite, very common |
| 存じません | I do not know (humble) | Very polite, formal |
| 分かりかねます | I am unable to say | Customer service, formal |
Why a bare shirimasen can sound cold
Imagine a colleague asks where a file is, and you reply shirimasen and keep typing. In Japanese that can feel like "no idea, not my problem". The verb itself is fine; the trouble is that it offers nothing further and can suggest you are distancing yourself from the matter.
Wakaranai, by contrast, implies you tried and could not work it out. That is why, even for straightforward facts, many people choose wakaranai or wrap shiranai in softeners. Tone matters too: a slight pause, a lower voice and a small apology make either verb friendly.
| Japanese | Romaji | Meaning |
|---|---|---|
| 知りません。 | Shirimasen. | I don't know. (can sound curt alone) |
| すみません、知らないです。 | Sumimasen, shiranai desu. | Sorry, I don't know. (softer) |
| すみません、ちょっと分からないです。 | Sumimasen, chotto wakaranai desu. | Sorry, I'm not really sure. |
| そこまではちょっと分からないですね。 | Soko made wa chotto wakaranai desu ne. | I'm not sure about that level of detail. |
Everyday polite ways to say I don't know
In shops, on the street and with acquaintances, the most natural pattern is apology plus chotto plus wakaranai desu. Chotto here does not mean "a little" literally; it signals hesitation and softens the refusal, much like English "I'm afraid".
If a stranger asks for directions and you have no idea, it is common to explain why, which sounds friendlier than a flat no.
| Japanese | Romaji | Meaning |
|---|---|---|
| すみません、ちょっと分からないです。 | Sumimasen, chotto wakaranai desu. | Sorry, I'm not sure. |
| ごめんなさい、この辺の者じゃないので。 | Gomen nasai, kono hen no mono ja nai node. | Sorry, I'm not from around here. |
| 私もよく分からないんです。 | Watashi mo yoku wakaranai n desu. | I'm not really sure myself. |
| 駅員さんに聞いたほうがいいかもしれません。 | Eki-in-san ni kiita hō ga ii kamo shiremasen. | It might be best to ask the station staff. |
| どうでしょうね。 | Dō deshō ne. | Hmm, I wonder. (polite hedge) |
Dō deshō ne is useful when you have an opinion but do not want to commit, or when the question has no clear answer. It sounds thoughtful rather than evasive.
At work: humble and customer-service versions
In business Japanese, "I don't know" rarely stands alone. Admitting you do not know is fine, but it is expected to come with an apology and a next step. The humble verb zonjiru replaces shiru: 存じません (zonjimasen) or, when talking about a person, 存じ上げません (zonjiagemasen), I am not acquainted with them.
分かりかねます (wakarikanemasu) means "I am unable to say" and is common in customer service. It can also be a polite way of saying "I can't give you that answer", so it is useful when a question is outside your role. 把握しておりません (haaku shite orimasen), I have not been informed, is common in internal communication.
| Japanese | Romaji | Meaning |
|---|---|---|
| 申し訳ございません、存じません。 | Mōshiwake gozaimasen, zonjimasen. | I'm very sorry, I do not know. |
| その方は存じ上げません。 | Sono kata wa zonjiagemasen. | I am not acquainted with that person. |
| 申し訳ございませんが、私では分かりかねます。 | Mōshiwake gozaimasen ga, watakushi de wa wakarikanemasu. | I'm very sorry, but I'm not able to say. |
| その件は把握しておりません。 | Sono ken wa haaku shite orimasen. | I haven't been informed about that matter. |
| 確認して、折り返しご連絡いたします。 | Kakunin shite, orikaeshi go-renraku itashimasu. | I'll check and get back to you. |
| 担当の者に確認いたします。 | Tantō no mono ni kakunin itashimasu. | I'll check with the person in charge. |
Turning I don't know into a helpful answer
The phrase that follows "I don't know" often matters more than the phrase itself. Offering to look something up, ask someone or suggest where to go shows good faith and keeps the conversation friendly.
These follow-ups work in both polite and casual speech; just change the ending.
| Japanese | Romaji | Meaning |
|---|---|---|
| 調べてみます。 | Shirabete mimasu. | I'll look it up. |
| 聞いてみますね。 | Kiite mimasu ne. | I'll ask someone. |
| 分かったら連絡します。 | Wakattara renraku shimasu. | I'll let you know once I find out. |
| 確か受付で聞けると思います。 | Tashika uketsuke de kikeru to omoimasu. | I think you can ask at reception. |
| ちょっと調べるね。 | Chotto shiraberu ne. | Let me check. (casual) |
Casual ways among friends
With friends and family, plain forms are normal: wakaranai, or the very common spoken wakannai, and shiranai. Among friends, shiranai is not cold at all; the warmth comes from the relationship and tone.
Sā and sā nē are shrugs meaning "who knows". Shiran is common in Kansai and among some male speakers. Shiru ka, "how should I know", is genuinely rude and best kept for recognising anger in dramas.
| Japanese | Romaji | Meaning |
|---|---|---|
| 分かんない。 | Wakannai. | Dunno. |
| 知らない。 | Shiranai. | I don't know. |
| さあね。 | Sā ne. | Who knows. |
| どうだろう。 | Dō darō. | Hmm, I wonder. |
| 全然分かんないや。 | Zenzen wakannai ya. | I have no clue at all. |
| 知らん。 | Shiran. | Dunno. (Kansai, blunt) |
| 知るか。 | Shiru ka. | How should I know? (rude) |
Not understanding versus not knowing
Learners often need "I don't understand what you said" rather than "I don't have the answer". Wakarimasen covers both, but being specific helps the other person help you. Did you not hear, not know a word, or not follow the meaning?
Asking about a word with tte nan desu ka, "what is ...?", is quick and natural, and much more useful than a general wakarimasen.
| Japanese | Romaji | Meaning |
|---|---|---|
| すみません、聞き取れませんでした。 | Sumimasen, kikitoremasen deshita. | Sorry, I didn't catch that. |
| もう一度お願いします。 | Mō ichido onegai shimasu. | Once more, please. |
| 「締め切り」ってなんですか。 | "Shimekiri" tte nan desu ka. | What does shimekiri mean? |
| 意味がよく分かりません。 | Imi ga yoku wakarimasen. | I don't quite understand the meaning. |
| もう少しゆっくり話していただけますか。 | Mō sukoshi yukkuri hanashite itadakemasu ka. | Could you speak a little more slowly? |
Common mistakes
- Answering every question with a flat shirimasen. Use chotto wakaranai desu, or add sumimasen and a follow-up.
- Using wakarimasen when you mean you disagree. Wakarimasen means you cannot tell; for disagreement, try sō desu ka nē or chotto chigau to omoimasu.
- Saying zonjiagemasen for facts, such as a meeting time. Keep it mainly for people.
- Using sā to a customer or superior. It sounds like a shrug; say wakarikanemasu or o-shirabe itashimasu instead.
- Stopping at I don't know at work. Always add a next step, even a simple kakunin shimasu.