Using the folowing formula, you can calculate what size paper
you need to start with in order to fold an envelope of a certain size.
a = hight of finished envelope
b = width of finished envelope
A = hight of paper
B = width of paper
If you want the finished envelope to be 3 inches by 5 inches (a = 3 and b = 5),
A = (a x 16) / 5 = (3 x 16) / 5 = 9.6 inchesSo, the starting sheet of paper should be 9.6 inches high and 7.4 inches wide.
B = ((a x 4) / 5 ) + b = ((3 x 4) / 5 ) + 5 = 7.4 inches