The Excel ISOWEEKNUM function takes a date and returns a week number (1-54) that follows ISO standards, where weeks begin on Monday and week number 1 is assigned to the first week in a year that contains a Thursday.
Get ISO week number for a given date
A number between 1 and 54.
date - A valid Excel date in serial number format.
The ISOWEEKNUM function returns a week number based on ISO standards. Under this standard, weeks begin on Monday and the week number 1 is assigned to the first week in a year that contains a Thursday.
To get the week number from the day from a date, you can use the WEEKNUM function. In the example shown, the formula in C5, copied down, is:
With the date January 5, 2016 in B5, WEEKNUM returns 2 as the...
The Excel WEEKNUM function takes a date and returns a week number (1-54) that corresponds to the week of year. The WEEKNUM function starts counting with the week that contains January 1. By default, weeks begin on Sunday.