Video
Let’s watch this short video for a quick overview.
Source: gokigen japanese official YouTube Channel
Introduction
Have you ever wanted to explain something politely or say “actually…” in Japanese?
In English, we might say:
- “Actually, I have a headache.”
- “That’s because the bus didn’t come.”
In Japanese, the go-to expression for giving explanations or background information is:
～んです
= actually / in fact / you see…
It’s used when someone asks why or when you want to give a reason or context for something.
Let’s explore how to use this expression naturally in daily Japanese!
1. Basic Structure
Grammar Pattern: [Short form] + んです
| Type | Example |
|---|---|
| Verb | 来なかったんです (Something did not come) |
| い-adjective | 忙しいんです (I’m busy) |
| な-adjective | きれいなんです (It’s beautiful, you see) |
| Noun | 公務員なんです (I am a government employee) |
📌 Use short form before んです, and if it’s a な-adjective or noun, don’t forget to add な before んです!
[Tip] Casual Forms: “〜んだ” and “〜の”
In casual speech, んです becomes んだ (plain form) or の (softer, often used in spoken Japanese).
- 〜んだ is the casual short-form version of んです.
- 〜の is another casual variant. It has a softer tone and can sometimes sound slightly feminine, depending on the speaker and context.
Example Conversation (Casual Speech)
A: どうして遅刻したの？
Why were you late?
B: バスが来なかったんだ。／ バスが来なかったの。
The bus didn’t come (so I was late).
2. When Do We Use ～んです？
In Japanese, you can use the explanatory expression んです to provide additional information, give an explanation, or emphasize a point.
Use 〜んです when:
- Explaining a situation
- Answering a “why” question
- Provide additional information
3. Example Situations
When explaining your situation:
頭が痛いんです。
I actually have a headache. (to the doctor)
今日は忙しいんです。
Actually, I’m busy today. (In response to a dinner invitation from a colleague)
試験があるんです。
The thing is, I have a test. (In response to a friend’s invitation)
When answering “Why?”
Note on using 〜んです with question words
The phrase 〜んです is often used with question words like どうして (“why”). When someone asks どうして〜んですか, it is natural to answer with 〜んです as well.
In casual speech, the pattern becomes どうして〜の？ — not どうして〜んだ？, which can sound rough.
Another common question word used with 〜んです is どうした (“what’s wrong / what happened?”):
- どうしたんですか。
- どうしたの？
Example
Yuka was late for class:
どうして遅刻したんですか。
Why were you late?
ごめんなさい、バスが遅れたんです。
I’m sorry, the bus was delayed.
Emi ran into a friend crying in a cafe:
どうして泣いているの。
Why are you crying?
映画が悲しかったんだ。
The movie was sad, that’s why.
Provide additional information
An acquaintance sees your car:
A: すてきな車ですね。= Nice car.
B: 父の（車）なんです。= Actually, it’s my father’s.
A co-worker is looking at a brand new computer you bought on sale:
A: あたらしいパソコンですね。= It’s a new computer.
B: とてもやすかったんです。= It was actually very cheap.
4. Conjugation Rules
| Type | Short Form | + んです |
|---|---|---|
| Verb | 行く | 行くんです |
| Verb (negative) | 行かない | 行かないんです |
| い-adjective | 忙しい | 忙しいんです |
| い-adjective (negative) | 忙しくない | 忙しくないんです |
| な-adjective | きれい | きれいなんです |
| な-adjective (negative) | きれいじゃない きれいではない | きれいじゃないんです きれいではないんです |
| Noun | 医者 | 医者なんです |
| Noun (negative) | 医者じゃない 医者ではない | 医者じゃないんです 医者ではないんです |
5. Practice Time!
Turn these into 〜んです sentences:
| Situation | Sentence |
|---|---|
| Actually, I’m tired. | 疲れたんです。 |
| Actually, I have no time. | 時間がないんです。 |
| Actually, I’m not a student. | 学生じゃないんです。 |
| Actually, I received it from my friend. | 友だちにもらったんです。 |
| Actually, today is my birthday. | 今日は誕生日なんです。 |
FAQ – Frequently Asked Questions
- QWhat’s the difference between です and んです?
- A
です simply reports a fact, んです explains or emphasizes a situation.
Example:- 忙しいです。= I’m busy (neutral)
- 忙しいんです。= I’m busy (and that’s why I can’t come)
- QWhat specific feeling or nuance does ～んです add besides just explanation?
- A
While its core function is explanation or providing context, ～んです often adds a feeling of wanting the listener to understand your situation or reasoning. It can make a statement sound more personal, softer, or less abrupt. In questions (～んですか), it can show genuine curiosity, concern, or sometimes mild surprise (“Oh, is that why…?”). It helps bridge the gap between speaker and listener by implicitly saying “here’s the background/reason/situation.”
- QCan I overuse ～んです? When is it better to just use です/ます?
- A
No, definitely avoid overusing it! Use standard です/ます when simply stating facts, making neutral observations, or when no particular explanation, justification, or background context is needed.
Adding んです to every sentence sounds unnatural and can make you seem like you’re constantly explaining yourself or making excuses.
Reserve ～んです for situations where there’s a reason to provide context, answer an implicit or explicit “why,” or soften your statement.
- QWhy do I use な before んです with な-adjectives and nouns in the present affirmative (e.g., きれいなんです)? Why not だ?
- A
This is a specific grammatical rule for connecting present affirmative な-adjectives and nouns to んです (and its casual form の). While the standard plain form ends in だ (e.g., きれいだ), this だ changes to な when immediately followed by んです/の. Think of な as the special “linking form” used in this specific context. For other forms like past tense (きれいだった) or negative (きれいじゃない), you use their standard plain forms directly before んです.
- QHow does using ～んです compare to using ～から (because)? Can they be used together?
- A
They serve slightly different but related functions. ～から explicitly marks the reason clause. ～んです adds an explanatory nuance, often to the result or the statement containing the reason. They frequently appear together: [Reason Plain Form] + から, [Result/Situation Plain Form] + んです.
Example: 「頭が痛かったから、学校を休んだんです。」(Atama ga itakatta kara, gakkou o yasunda n desu. – Because my head hurt, I took the day off school, you see.) The から gives the direct cause, while the んです explains why you’re stating the result (implicitly answering “Why didn’t you go to school?”).
- QCan asking questions with ～んですか sometimes sound demanding or like I’m prying?
- A
Yes, it can. While ～んですか often sounds softer or more curious than a direct question, the nuance depends greatly on context and tone of voice. Importantly, ～んですか can also be used without a question word. In this case, it is usually asked when the speaker is:
- confirming something they noticed or heard, or
- expressing surprise, concern, or slight irritation.
Seeing someone who looks unwell:
頭が痛いんですか。
Do you have a headache?
はい、少しねつがあるんです。
Yes, I think I have a bit of a fever.Noticing someone suddenly packing to leave:
どこに行くんですか。
Where are you going?
アルバイトに行くんです。
I’m going to my part-time job.
え、アルバイトに行くんですか。
Oh, you’re going to your part-time job? (surprise or mild disbelief)Because ～んですか can reflect the speaker’s emotional reaction, asking sharply or repeatedly may sound demanding, accusatory, or prying. Used gently, it expresses curiosity, concern, or the desire to clarify something.
Conclusion
Using 〜んです helps you sound more natural, polite, and connected in conversation. It’s a must-know pattern for:
✅ Giving explanations
✅ Expressing reasons
✅ Answering questions with nuance
🎯 Try it now:
Write 3 things about your day using 〜んです！
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