Hi Wayne,
In your example the margin is 50% not 40% the formula to use is

Cell A1 = Selling price
Cell A2=Cost

=1/(1+(A2/A1))

other way is to simple deduct the cost from the Selling price divided by 100
=(A1-A2)/100

"wayne" wrote:

new to excel-- i would like to set up a formula to calculate the margin
percentage.

ex -- cost divided by retail= markup, markup divided by 1. the markup

1.00/1.50 = .667

.667/1.667=40% gross margin