Translation guide
How to express how long something lasts or takes in Japanese. The key pattern is using a time period followed by 間 (あいだ) or just the period word itself, depending on context.
2時間
for two hours
どのくらいかかりますか？
How long does it take?
Expressing how long an event or state continues, such as 'for two hours' or 'all day'.
Add 間 (かん) to a time period to indicate duration. This is the most common and neutral way to say 'for X time'.
2時間待ちました。
I waited for two hours.
彼は3年間日本に住んでいました。
He lived in Japan for three years.
For some time words like 週 (しゅう, week) or 日 (にち, day), 間 is often omitted in casual speech or when the duration is clear from context. However, including 間 is always safe.
Means 'period' or 'duration' as a noun. Used in formal contexts or when referring to a defined span of time.
契約期間は1年です。
The contract period is one year.
Inquiring about the duration of an action or event.
The most common way to ask 'how long'. どのくらい literally means 'about how much' and can be used for time, distance, etc.
どのくらいかかりますか？
How long does it take?
どのくらい待ちましたか？
How long did you wait?
Synonymous with どのくらい, slightly more casual.
どれくらい勉強しましたか？
How long did you study?
Use specific time unit question words when you expect an answer in that unit.
何時間寝ましたか？
How many hours did you sleep?
Expressing 'from X to Y' or 'between X and Y'.
The standard pattern for 'from X until Y'. Can be used with time points or events.
9時から5時まで働きます。
I work from 9 to 5.
月曜日から金曜日までです。
It's from Monday to Friday.
Describing how long a state has been continuing, often with ている form.
Adding も after the time period emphasizes the length of time, often translated as 'for as long as' or 'for a whole X'.
彼は10年もここに住んでいます。
He has been living here for as long as ten years.
Used to say 'since X ago', indicating the start of a duration.
1時間前から待っています。
I have been waiting since an hour ago.
When 間 is read as あいだ, it means 'while' or 'between', not a simple duration. For duration, use the suffix かん.
夏の間、海で泳いだ。
During the summer, I swam in the sea.
間 indicates the length of time something lasts. 以内 means 'within' a time limit, focusing on the deadline.
1時間以内に終わります。
I will finish within one hour.