# Calculate the week from a date, Jan 1st = week 1

I'm looking for a calculated column formula which will calculate 1st January 2022 as week 1. I'm in Europe, so, like most of the world, my date field 01/01/2022 = 1st January 2022.

I would like 1st January til 7th January to be week 1. 8th January - 14th January should be week 2.

I've found loads of articles for calculating other types of dates like the ISO date or Financial Year dates, but mine should be simple and yet I can't seem to find a formula which can do this. The closest I found was by Nate Chamberlain, but it didn't return the weeks correctly for me.

## Update - extra notes relating to Santosh's answer

For other years, past and future, a separate calculated column is needed. Please see the screen shot below to illustrate why this is needed.

The formula provided by Santosh needs to be adjusted very slightly to allow it to function for each year; very simple.

I have created below formula to calculate week number starting on 1st of Jan 2022. Refer attached screenshot for the output.

``````=ROUNDDOWN(DATEDIF(DATE(2022,1,1),[datefield],"d")/7,0)+1
``````

You need to replace datefield with your date column, the data type returned by this formula can be used as Number or single line of text. This should work for any regional settings, please confirm.

This formula can be used to calculate week number starting with any starting date(e.g. In this case we have used 1st Jan, 2022).

Output :

I hope this will work for you :)

• Thanks Santosh, that works really well! I've updated my question with a note for other users regarding how to handle past or future years. Jan 11, 2022 at 13:31
• Thanks for the reply. I'm glad to hear that solution worked for you. Jan 11, 2022 at 16:34

I found that Santosh's answer worked, but my case required that the week number is relative to the year of the respective [DATEFIELD], not based on a static starting date. I've adapted his answer and found that the following code provided what I need.

``````=ROUNDDOWN(DATEDIF(DATE(YEAR([DATEFIELD]),1,1),[DATEFIELD],"d")/7,0)+1
``````
• Good work Brad! Jan 13, 2023 at 9:57

So glad I found this. I found Brad's answer met my needs more precisely. Then I added code to show a blank field if there is no date in the date field. My code looks like this and will display an empty field:

``````IF(ISBLANK([DATEFIELD]),"",ROUNDDOWN(DATEDIF(DATE(YEAR([DATEFIELD]),1,1),[DATEFIELD],"d")/7,0)+1
``````