Translation guide
In Japanese, expressing 'several hours' depends on whether you are talking about a duration (how long something takes) or a point in time (how many hours from now or ago). The most common and versatile way is to use 数時間 (すうじかん) for duration. For 'a few hours', ２、３時間 (に、さんじかん) is very natural. When referring to a point in time, use 数時間後 (すうじかんご) for 'in a few hours' or 数時間前 (すうじかんまえ) for 'a few hours ago'.
Expressing that an action or state lasts for several hours.
The standard, neutral way to say 'several hours' as a duration. Suitable for both spoken and written Japanese.
会議は数時間続いた。
The meeting lasted for several hours.
数時間待ちました。
I waited for several hours.
Literally '2, 3 hours', this is a very common and natural way to say 'a few hours' or 'a couple of hours'. It implies a small, indefinite number, typically 2 or 3.
２、３時間で終わるよ。
It'll be done in a couple of hours.
２、３時間寝れば大丈夫。
If I sleep for a few hours, I'll be fine.
Means 'some hours' or 'a number of hours'. It is slightly more vague than 数時間 and can be used when the exact number is unknown or unimportant.
何時間かかかると思います。
I think it will take a few hours.
A more formal or literary expression meaning 'over the course of several hours' or 'for a period of several hours'. Often used in news reports or written narratives.
数時間にわたって停電が続いた。
The power outage continued for several hours.
Expressing that something will happen or happened several hours from now or before now.
Means 'in a few hours' or 'several hours later'. Used for future events relative to now or a reference point.
数時間後にまた来ます。
I'll come again in a few hours.
薬は数時間後に効き始める。
The medicine starts to take effect after a few hours.
Means 'a few hours ago' or 'several hours earlier'. Used for past events.
彼は数時間前に出かけました。
He went out a few hours ago.
A more casual way to say 'in a couple of hours' or 'after 2 or 3 hours'.
２、３時間後に電話するね。
I'll call you in a couple of hours.
Emphasizing that the duration is approximate, not exact.
Adding ほど (hodo) after 数時間 makes it explicitly 'about several hours' or 'approximately several hours'. It softens the statement and is very common in polite conversation.
数時間ほどお待ちいただけますか。
Could you wait for about a few hours?
Using くらい (kurai) with ２、３時間 gives a casual 'about 2 or 3 hours'. Very common in everyday speech.
２、３時間くらい昼寝した。
I took a nap for about a couple of hours.
数時間 (suujikan) is the most standard and neutral for 'several hours'. ２、３時間 (ni, sanjikan) is more colloquial and specifically implies 2 or 3 hours, often used for 'a couple of hours'. 何時間か (nanjikanka) is vaguer, meaning 'some hours' or 'an unspecified number of hours', and is common in spoken Japanese when you don't know or don't want to specify the exact number.
Do not try to directly translate 'several' as いくつかの (ikutsuka no) with 時間 (jikan). While いくつかの時間 is grammatically possible, it is unnatural and rarely used. Stick to 数時間 or ２、３時間.