noun which may take the genitive case particle 'no', noun
Used to describe something that is required or necessary, often in formal or business contexts. Commonly appears in phrases like 所要時間 (required time) or 所要経費 (necessary expenses).
The time required for this task is about 30 minutes.
Please submit the necessary documents.
It takes about ten minutes to get to the station.
Please prepare all the required documents for the application.
必須 stresses that something is indispensable or mandatory, whereas 所要 simply states what amount or item is required without implying it can't be skipped.
不要 means 'unnecessary', the direct opposite of 所要's sense of being required or needed.
所用 (しょよう) is a homophone meaning 'business, errand', completely different from 所要, which means 'required, necessary'.
Compound of 所 (place, extent) and 要 (need, necessity). The combination conveys the idea of 'what is needed for a given matter'.