Translation guide
Expresses that something happens or is the case for an unspecified or unknown reason. The Japanese equivalent depends on the speaker's attitude: vague uncertainty, curiosity, or a sense that the reason is inexplicable.
The speaker does not know or does not specify the reason, often with a nuance of 'I don't know why, but...'
The speaker feels the reason is beyond understanding or logic, often with a nuance of wonder or frustration.
Used when the speaker is genuinely puzzled and seeking an explanation, but states the fact without knowing the reason. More questioning in tone than なぜか.
どうしてか、彼はいつも遅刻する。
For some reason or other, he's always late.
Both mean 'for some reason', but なぜか is more casual and implies a simple lack of knowledge. どういうわけか suggests the speaker has considered possible reasons and still finds it inexplicable, adding a nuance of 'no matter how I think about it'.
なぜか彼女は怒っていた。
For some reason, she was angry. (I don't know why.)
どういうわけか彼女は怒っていた。
For some reason or other, she was angry. (I've thought about it, but I can't figure out why.)
なんだか is perfect when the reason is a gut feeling or an unexplainable mood. It often pairs with 気がする (feel like) or 感じがする (have a feeling).
どういうわけか、会議は中止になった。
For some reason or other, the meeting was canceled.
なぜか今夜は眠れない。
For some reason, I can't sleep tonight.
For some reason, I'm really tired today.
なぜか彼の名前が思い出せない。
For some reason, I can't remember his name.
Literally 'for what reason?', but used as 'for some reason or other'. Slightly more emphatic than なぜか, suggesting the speaker has thought about it but still can't figure out the reason.
どういうわけか、今日は電車が空いていた。
For some reason or other, the train was empty today.
Conveys a vague feeling or intuition. Often used when the reason is emotional or hard to pinpoint. More casual than なぜか.
なんだか今日はいいことがありそうな気がする。
For some reason, I feel like something good will happen today.
Similar to なぜか but slightly more colloquial and emphatic. Often used in spoken language.
なぜだかわからないけど、彼が嫌いだ。
For some reason, I don't like him.
Literally 'I don't know why, but...'. Emphasizes the speaker's lack of knowledge. Slightly more formal or literary.
何故か知らないが、その日は誰も来なかった。
For some reason or other, nobody came that day.
A more literal translation, 'for what reason?', used as a rhetorical question. Sounds a bit stiff and is less common in everyday speech.
何の理由か、彼は突然笑い出した。
For some reason or other, he suddenly burst out laughing.
なんだか寂しい気がする。
For some reason, I feel lonely.
For some reason, I feel lonely.