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.
for two hours
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'.
I waited for two hours.
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.
I will travel for one week.
Means 'period' or 'duration' as a noun. Used in formal contexts or when referring to a defined span of time.
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.
How long does it take?
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.
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'.
When 間 is read as あいだ, it means 'while' or 'between', not a simple duration. For duration, use the suffix かん.
During the summer, I swam in the sea.
1週旅行します。
I will travel for one week. (casual, 間 omitted)
契約期間は1年です。
The contract period is one year.
How long did you wait?
Synonymous with どのくらい, slightly more casual.
How long did you study?
Use specific time unit question words when you expect an answer in that unit.
How many hours did you sleep?
I work from 9 to 5.
It's from Monday to Friday.
He has been living here for as long as ten years.
Used to say 'since X ago', indicating the start of a duration.
I have been waiting since an hour ago.
間 indicates the length of time something lasts. 以内 means 'within' a time limit, focusing on the deadline.
I will finish within one hour.