Translation guide
The English phrase "night and day" is used to emphasize a stark contrast or to describe continuous, unceasing activity. This guide helps learners express these ideas naturally in Japanese.
To emphasize that two things are completely different or opposite, like night and day.
Their personalities are night and day. · The difference is night and day.
To describe an action or state that continues without stopping, day and night.
They worked night and day to finish the project. · The factory runs night and day.
Means 'regardless of day or night' or 'around the clock.' Often used for continuous effort or availability.
彼らは昼夜を問わず働いた。
They worked night and day.
The direct translation 「夜と昼」(よるとひる) is not used idiomatically in Japanese to express contrast or continuous action. Use the phrases above instead.
Both mean a stark difference, but 月とすっぽん is more colloquial and vivid, while 雲泥の差 is more formal and often used in writing or serious evaluations.
A common idiom meaning 'as different as the moon and a soft-shell turtle'—two round things that are nothing alike. Used for stark contrasts.
あの二人の性格は月とすっぽんだ。
Their personalities are like night and day.
Literally 'the difference between clouds and mud.' A somewhat formal or literary expression for a huge gap.
両者の実力には雲泥の差がある。
There's a night-and-day difference in their abilities.
Literally 'a difference like heaven and earth.' Emphasizes an extreme contrast.
この二つの製品の品質は天と地ほどの差だ。
The quality of these two products is night and day.
A straightforward way to say 'completely different.' Not an idiom, but natural and clear.
彼の考え方は私とは全く違う。
His way of thinking is night and day from mine.
Means 'cannot be compared' or 'there's no comparison.' Used when one thing is vastly superior or different.
前のバージョンとは比べ物にならないほど良くなった。
It's improved so much it's like night and day compared to the previous version.
A concise adverb meaning 'day and night' or 'constantly.' Common in both speech and writing.
日夜努力を続けている。
I'm continuing my efforts night and day.
Literally 'without sleeping.' Used when someone works through the night, emphasizing lack of sleep.
寝ずに看病した。
I nursed them night and day (without sleeping).
Means 'all the time' or '24/7.' Slightly informal, emphasizes constant, uninterrupted activity.
四六時中ゲームをしている。
He plays games night and day.