The Excel function: WEEKNUM
Description
Returns the week number of a specific date. For example, the week containing January 1 is the first week of the year, and is numbered week 1.
There are two systems used for this function:
- System 1 The week containing January 1 is the first week of the year, and is numbered week 1.
- System 2 The week containing the first Thursday of the year is the first week of the year, and is numbered as week 1. This system is the methodology specified in ISO 8601, which is commonly known as the European week numbering system.