Working out date for invoice payment formula

Hi All, I need a formula to work out 21 days from the Friday after a delivery has been made during a week, eg delivery date is Tuesday 27th October, and my payment date is 21 days from the Friday of the week of delivery ie 21 days from Friday 30th October (so Friday 20th November). Is this possible to do in excel?

Thanks in advance

Is your excel version still 2007? Not many are still using it? Some functions that more recent versions support make this easier to solve

=A1+7-WEEKDAY(A1+1) finds the next Friday (although returns the day if it is a Friday, your were not clear on this)

adding 21 to this gives you the date

=A1+7-WEEKDAY(A1+1)+21

=A1+28-WEEKDAY(A1+1)