Hi
if B1 contains the billing start and B2 the billing end try in F4 (note: in
your example you seem to exclude the start and end date of the free trail
duration)
=NETWORKDAYS($B$1,$B$2)-IF(COUNT(D4:E4),NETWORKDAYS(MAX($B$1,D4)+1,MIN($B$ 2,E4)-1),0)

But not totally sure what should happen for all cases of your trial period.
But this should give you something to start with

--
Regards
Frank Kabel
Frankfurt, Germany
"carl" schrieb im Newsbeitrag
...
Hi. I am trying to use the Networkdays formula in ColF but need to have
the
formula check the Billing Start, Billing End, FreeTrail Start, FreeTrail
End
dates to determine the # of billing days. For example, for Product AN,
since
the free trail starts after the billing start date and ends before the
billing end date the formula in ColF needs to count the business days
between
12/1-12/6 (4) and 12/15-12/31 (13).

Thank you in advance.

B C D E F

Billing Start 1-Dec
Billing End 31-Dec
Customer Product Free Trail Start Free Trail End # Billing Days
ABC AN 6-Dec 15-Dec 17
ABC IACI 23
ABC LSI 6-Dec 15-Jan 4