Need to adapt SUM PRODUCT to measure calendar and work days each Week between dates

Attached Table in A2 - E10 lists the Planned and Actual Start and Finish Dates for four Activities.

GANTT BY MONTH in rows 29 - 37 works perfectly, using SUM PRODUCT to establish how many days each Calendar month are covered by the Date span:
E.g. C30 (Planned Activity 1 (3rd - 10th Jan) shows 8 days in January:

=IF(SUMPRODUCT(--(MONTH(ROW(INDIRECT($C4 & ":" & IF($D4="",TODAY(),$D4))))=MONTH(C$29)))>0,SUMPRODUCT(--(MONTH(ROW(INDIRECT($C4 & ":" & IF($D4="",TODAY(),$D4))))=MONTH(C$29))),"")

First challenge is failing to adapt the Formula so it establishes how many days each Calendar WEEK are covered by the Date Span:

E.g. C16 (Planned Activity 1 (3rd - 10th Jan) in week 1 SHOULD show 5 days in week 1:

=if(SUMPRODUCT(--(WEEKNUM(ROW(INDIRECT($C3 & ":" & IF($D3="",TODAY(),$D3))))=WEEKNUM(C$15)))>0,SUMPRODUCT(--(WEEKNUM(ROW(INDIRECT($C3 & ":" & IF($D3="",TODAY(),$D3))))=WEEKNUM(C$15)))>0,"")

Unfortunately, as shown on row 16, it generates weeks 1 - 7 as 5s, then weeks 8 - 14 as 3s (SHOULD be 5 in week 1 and 3 in week 2).

Second challenge is the need to adapt the formula so the User can SUMPRODUCT working days (assuming Mon - Fri) as well as Calendar days.

All solutions, alternatives and recommendations welcome as ever.

Ochimus

First of all, your calendar-day monthly formula can be substantially simplified like this:

=MAX(0,MIN(IF($D3,$D3,TODAY()),EOMONTH(C$29,0))-MAX($C3,C$29)+1)

The corresponding calendar-day weekly formula can look like this to produce the desired results:

=MAX(0,MIN(IF($D3,$D3,TODAY()),WORKDAY.INTL(MIN($C$3:$C$10)+1,-1,"1111110")+7*C$15-1)-MAX($C3,WORKDAY.INTL(MIN($C$3:$C$10)+1,-1,"1111110")+7*(C$15-1))+1)

I am attaching a modified file with three tabs: Calendar Days, Working days, and Selectable Calendar/Working -- see if they meet your needs.

Root,

Many thanks for the prompt response, the more elegant Month formula and the Weekly solution.

But value clarification on one point? In the Weekly formula you set the weekend as a fixed "1111110". Should that not have two options based on the Calendar/Workday choices in F3? If the formula starts the week on Sunday, and the User has selected Workdays, should that not be "0111110", and if it starts on Monday "1111100"?

Ochimus