Time between two dates

I am trying to put together a formula that determines the amount of work days between two dates. I only want to count Monday-Sundays, and occasionally be able to also remove holidays. However, the formula I am currently using only counts whole days, which is throwing off my accuracy. Each date has a time stamp and I am looking to calculate the days down to specifics (i.e. 1.3 days). Here's an example:

12/2/2014 18:00 12/16/2014 1:48 formula: =SUM(INT((WEEKDAY(G14-{2,3,4,5,6,7})+H14-G14)/7))-SUMPRODUCT(--ISNUMBER(MATCH(ROW(INDEX($P:$P,G14):INDEX($P:$P,H14)),$P$1412:$P$1416,0)))

Result: 12

Actual: 11.32

I wouldn't mind doing the math manually except that there are thousands of these and that would be too time consuming. Thank you!

It's working for some of the dates, but when I get down the list, it isn't working. for example:

12/21/2014 18:00 to 12/22/2014 7:47

Formula output: 1.574

Actual: .574