I have a formula I use to calculate a date that is 21 days after a given
date.

=WORKDAY(C3,21)+7-WEEKDAY(WORKDAY(C3,21)-6)

This would return a date 21 days from a given date plus the Friday after 21
days. (not sure this made sense)

Anyway, I need to modify the formula to return a date that is based on Net
30 from a given date.