[Weekday()] Count the number of say 'Wednesday' between Date 1 and Date 2 -- This works but why?

[pivotpp]

[FONT=&quot]Hi all,[/FONT]
[FONT=&quot]My goal is to count the number of a specific day of the week, say a Wednesday or Friday or Sunday between Date 1, say 1/10/2015 and Date 2, say 8/10/2015.

[/FONT]
[FONT=&quot]I actually have the answer, as this formula works to count the number of Sundays and does everything I need: =INT((WEEKDAY($B$1- 1)-$B$1+$B2)/7)[/FONT]
[FONT=&quot]B1 = Date 1[/FONT]
[FONT=&quot]B2= Date 2[/FONT]
[FONT=&quot]And the 1 is Sunday, 2 is Monday ...7 is Saturday.[/FONT]
[FONT=&quot]
I've been scratching my head though as to WHY it works. The only that drives me crazier than something not working is something that works and not knowing the rationale behind it.

[/FONT]
[FONT=&quot]If anyone can breakdown the parts and explain why it works, would be very appreciative.

[/FONT]
[FONT=&quot]Thanks in advance[/FONT]

 

[Marcelo Branco]

I had seen this formula before and, like you, hadn't fully understood its logic. So i did some searches and found this excellent explanation by Barry Houdini in an old thread.
https://www.mrexcel.com/forum/excel...-number-days-except-sunday-2.html#post1794345

Enjoy!

M.