I need Excel to automatically provide me a week number based off of a starting date (01/01/2017) and other dates to follow. For example, week number 1 starts off with January 2nd 2017 (since the first week of the year starts on the first full week in the month [January 1st would actually fall under week 52]) So any date entered from January 2nd - January 8th would be considered week 1, January 9th - January 15th would be considered week 2, etc...

Can someone help me by developing a formula that suits what I am looking for?



Many thanks!!

How about

=ISOWEEKNUM(A1)

That works, thank you very much! I recall many years ago, circa 2009-2010 that I requested assistance with this same thing and the formula was super extensive but I suppose that ISOWEEKNUM(A1) wasn't available at this time. I appreciate you!

Ok, so the ISOWEEKNUM(A1) works but I need more that just that formula. Here is what I am trying to do... I have a landscaper that wants to pick up flowers that I am growing specifically for him and he wants them on the week of October 2nd. Knowing that his flowers will take 8 weeks to grow, I want excel to calculate what week in the year I should propagate his flowers so they're ready by the week of October 2nd. Does that make sense?

If you have October 2nd. (as date) in A1:

=ISOWEEKNUM(A1)-8

Awesome, thank you!