The 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. WEEKNUM takes two arguments: a date, and (optionally) return_type, which controls the scheme used to calculate the week number.
By default, the WEEKNUM function uses a scheme where week 1 begins on January 1, and week 2 begins on the next Sunday (when the return_type argument is omitted, or supplied as 1). With a return_type of 2, week 1 begins on January 1, and week 2 begins on the next Monday. See the WEEKNUM page for more information.
ISO week number
ISO week numbers, start on the Monday of the first week in a year with a Thursday. This means that the first day of the year for ISO weeks is always a Monday in the period between Jan 29 and Jan 4. Starting with Excel 2010, you can generate an ISO week number using 21 as the return_type:
If you need to get the day name (i.e. Monday, Tuesday, etc.) from a date, there are several options depending on your needs. Do you want to convert the date into a day name? If you want to convert the date value to a text value, you can use the TEXT...
The MONTH function takes just one argument, the date from which to extract the month. In the example shown, the formula is: = MONTH ( B4 ) where B4 contains the dateJanuary 5, 2016. The MONTH function returns the number 1 representing the month(...
The YEAR function takes just one argument, the date from which you want to extract the year. In the example, the formula is: = YEAR ( B4 ) B4 contains a date value for January 5, 2016. The YEAR function returns the number 2016 representing the year...
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.
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.
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