どうして・なぜ・なんで
Three ways to ask “why”
You’ll be able to ask why in three registers and choose the one fitting your situation.
どうして昨日来ませんでしたか。
doushite kinou kimasen deshita ka.
What do you think this sentence means?
Why didn’t you come yesterday?
Ask for a reason
All three can mean “why.” どうして is neutral and common, なぜ can sound more formal or analytical, and なんで is very common in casual conversation.
どうして日本語を勉強していますか。
doushite nihongo o benkyou shite imasu ka.
Why are you studying Japanese?
なぜ日本に来ましたか。
naze nihon ni kimashita ka.
Why did you come to Japan?
なんで食べないの？
nande tabenai no?
Why aren’t you eating?
Put the why-word before the sentence
Place the chosen word near the beginning of the question. In polite speech, the sentence can still end in か.
どうして遅れましたか。
doushite okuremashita ka.
Why were you late?
なぜこの道を選びましたか。
naze kono michi o erabimashita ka.
Why did you choose this route?
なんで笑っているの？
nande waratte iru no?
Why are you laughing?
Choose the tone that fits
Use どうして as a safe general choice. なぜ often fits formal explanation, while なんで sounds more conversational and can sound strong depending on tone.
どうして is neutral; なぜ is formal or analytical; なんで is conversational.
どうして来なかったんですか。
doushite konakatta n desu ka.
Why didn’t you come?
なぜ必要ですか。
naze hitsuyou desu ka.
Why is it necessary?
なんでそんなに急ぐの？
nande sonna ni isogu no?
Why are you in such a hurry?
どうして日本語を勉強しますか。
doushite nihongo o benkyou shimasu ka.
Why do you study Japanese?
どうして昨日学校に来ませんでしたか。
doushite kinou gakkou ni kimasen deshita ka.
Why didn't you come to school yesterday?
どうして朝ごはんを食べませんか。
doushite asagohan o tabemasen ka.
Why don't you eat breakfast?
14 more examples in the grammar path — free for a limited time.