I am using this formula to figure out how many days are between two dates
without including the weekends.
=NETWORKDAYS(J15,K15)-(WEEKDAY(J15,2)<6)+(1-MOD(3,1))*(WEEKDAY(J15,2)<6)+(MOD(K15,1)-1)*(WEEKDAY(K15,2)<6). I have placed this formula in cell N15.

It works very well, however in cell N15 the columns I am subtracting (cell
J15 and column K15) are missing dates. Could you tell me what I could
include in this formula so that it does not work when a cell in column J
and/or column K is missing a date? What I would like to happen instead is
for cell N15 (which contains the formula) to be blank or contain a zero
inside of it, when dates are missing from J15 and/or K15. Is this possible?