Calculate days in date range

I need to calculate the # of days in a service period within a date range and then prorate costs based upon those days. I've attached a sample worksheet and the date range I need to calculate on is 04/20/20 - 07/12/20. Thanks in advance.

I'm not sure if this is what you are looking for or not, but here's a formula I put in F2 and then copy down and across:
=IFERROR(DAYS(IF($C2>EOMONTH(F$1,0),EOMONTH(F$1,0),IF($C2<F$1,"",$C2)),IF($B2<F$1,F$1,IF($B2>EOMONTH(F$1,0),"",$B2)))+1,0)

In order for this to work (and be dynamic), I changed your headings to reflect the first day of the month (see attached). This can be handled many different ways, but for simplicity, I chose this.

Also, in Cell J2 I entered this:
=$E2/$D2*F2

I then copied this down and across.

Is this what you're looking for?

Hi Greg,

I copied and pasted the formula to calculate the days in F2 and it didn't work. I got the result '0'. Your tip to calculate J2, however, did work. Any further help on how to calculate F2?

I don't know how J2 could work if F2 didn't. I can't tell what the problem is if you don't attach your file. Did you open mine and did it show the right results?