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Addition of Week Number function in Powerapps

Currently, we don't have any direct way to calculate week number of the particular Date.

It would be better to have a function which displays the weeknumber for example: WeekNum("26-10-2017") = 43 to avoid usage of other source for this information and then retrieving back to Powerapps application.


Status: Under Review

Updating status and adding @GregLi

Regular Visitor

Please please please - dont forget the Europeans - the weekno in ISO is different from the weekno used in USA 
ISO: weekno: There are no splitted week-numbers across the year-change so 1.1.nnnn can be weekno 53 (of the year before) and the ISO week starts on mondays !!!

mfg Klaus Obd

Not applicable

This formula is working for me (in powerapps, there is another one for Sharepoint lists:




DateValue1_1= The date I want to know the Weeknum of.

DatePicker1=Date selector control with the date 12/31/2018

DatePicker1_1=Date selector control with the date 01/01/2018


It works only when the week starts on Monday, which is my case 😉

Not applicable

It has been more thank a year since this idea was voted . Is there any news ???

Kudo Collector

bump! update please.

New Member

i’ve been struggeling with this issue regarding finding the iso 8601 weeknumber in my Power App


So with a lot of help from Ryan in this post: i managed to deal with my issue


I did’nt want to use powerautomate in my app due to the app functionallity, so i took formulars and adapted it for Power Apps Here’s wat really worked for me:  If(RoundDown((DateDiff(DateValue(Year(DateAdd(DateValue(Text(ThisItem.’Start Time’)),4))&”/1/1″),DateAdd(DateValue(Text(ThisItem.’Start Time’)),4))+6)/7,0) = 0,53,RoundDown((DateDiff(DateValue(Year(DateAdd(DateValue(Text(ThisItem.’Start Time’)),4))&”/1/1″),DateAdd(DateValue(Text(ThisItem.’Start Time’)),4))+6)/7,0))


‘Start Time’ is in my case monday aka the start of the week