#Excel formula for week number iso

#Excel formula for week number iso

This system is the methodology specified in ISO 8601, which is commonly known as the European week numbering system.Įquivalent of the YEARFRAC-Function in Excel. System 2 The week containing the first Thursday of the year is the first week of the year, and is numbered as week 1.

System 1 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: The formula that I suggested will need a slight change though, because you have times as well as dates there could be some unwanted rounding up with the original formula which this will prevent. For example, the week containing January 1 is the first week of the year, and is numbered week 1. Rich (BB code): WEEKNUM (B2,13) for a Wednesday to Tuesday week. ',ĭocumentation.LongDescription = ' Returns the week number of a specific date. Equivalent of the YEARFRAC-Function in Excel. For example, the week containing January 1 is the first week of the year, and is numbered week 1. Result = if Return_type = 21 then IsoWeek else Defaultĭocumentation.Description = ' Returns the week number of a specific date. LastWeekOfThisYear = getNaiveWeek(#date(thisYear, 12, 28)),ĭefault = Date.WeekOfYear(Date, ConvertedNumber), LastWeekOfPriorYear = getNaiveWeek(#date(priorYear, 12, 28)), NaiveWeek = Number.RoundDown((ordinal – weekday + 10) / 7) WeekdayOfJan4th = getDayOfWeek(#date(Date.Year(inDate), 1, 4)), Result = 1 + Date.DayOfWeek(d, Day.Monday) IsoWeek = // this function comes from r-k-b on Github: PQ native Date.WeekFromYear starts to count from 0(Sunday) to 6(Saturday) as opposed to Excel from 1(Sunday) to 7(Saturday) For a detailled description about the options of the Return_types see the official documentation: (Date as date, optional Return_type as number) => The syntax for the excel WEEKNUM function, which outputs week number from a given date value, is as below: Where, serialnumber: is a date value for which you want to calculate the week number.