Translation guide
This guide covers how to ask about duration (how long something takes or lasts) and length (physical extent) in Japanese. The most common pattern uses どのくらい, but other expressions like どれくらい, どのぐらい, and なんじかん are also important depending on context.
How long does it take?
How long is it? (length)
The speaker wants to know how long an action or state lasts, or how much time something takes.
The most common and versatile way to ask 'how long' regarding time. It can be used for both duration and length of time. Often followed by かかりますか (takes) or ですか (is it).
How long does it take from here to the station?
How long have you been studying Japanese?
Very similar to どのくらい, slightly more casual. Interchangeable in most situations.
A variant of どのくらい with a voiced sound. Common in spoken Japanese, especially among younger speakers.
How long is the waiting time?
Specifically asks 'how many hours'. Use when you expect an answer in hours.
More explicit way to ask about time duration, literally 'how much time'. Slightly more formal.
The speaker wants to know the length of an object or distance.
Use this pattern to ask 'how long' about physical length. 長さ means 'length'.
How long is this table?
Casual variant of どのくらいの長さ.
How long is that river?
Asks specifically for length in meters. Replace メートル with other units like センチ (centimeters) or キロ (kilometers).
How many meters is this rope?
The speaker wants to know how long in terms of days, weeks, etc.
These three are largely interchangeable. どのくらい is the standard form. どれくらい is slightly more casual. どのぐらい is a voiced variant common in speech. All can be used for both time and physical length.
How long will we wait?
How long will we wait? (casual)
To ask 'how long has it been since...', use どのくらい前に or いつから. どのくらい alone can be ambiguous.
How long has it been since he came?
How long is the meeting?
How long have you been waiting?
映画はどれくらいの長さですか。
How long is the movie?
飛行機で何時間かかりますか。
How many hours does it take by plane?
How much time is needed for this task?
日本に何ヶ月滞在しますか。
How many months will you stay in Japan?
How many years have you worked here?