Get the week number of a date.
The Excel WEEKNUM function finds the week number of date and adjust as per week start day argument (optional). Example; to find week number starting from Monday for a date (05-06-2018: Cell-C7), use =WEEKNUM(B7,2) that returns ‘23’.
In simple term, WEEKNUM function helps you figure out which week of the year a date falls on.
serial_number – A valid argument of date, string representation or a serial number of a specific date
return_type [optional] – Setting custom start day of a week.
Returns an integer between 1 and 54.
The WEEKNUM function returns an integer between 1 and 54 that corresponds to the week number of a year as per given date argument.
The return type argument is optional, and the default is 1. There are two methods used for this function:
- The week containing January 1 is the first week of the year and represented as week 1.
- The week containing the first Thursday of the year is the first week of the year and expressed as week 1. This system is the methodology specified in ISO 8601, which is commonly known as the European week numbering system.
To customize the starting day of the 1st week of a calendar year following are the return type option available:
|Return_type||Week begins on|
|1 or omitted||Sunday|
|21||Monday (System 2)|