How many stamps do i need for 9' by12' envelope
Recenly, I had a 9 x 12 with 5 sheets of paper and a self-addressed, stamped #10 envelope and the postage was $1.05 if that helps you.
The amount of stamps you would need for a (I am assuming) 9 inch by 12 inch (not feet!) envelope depends on the weight. A one ounce envelope would require $.88 postage for first class mail in the United States.
It is not the quantity of stamps but the postage required based on weight and size.Go to www.usps.com and put in the size / weight/ stiffness and get your answer based on where you are shipping it to.
It depends on the weight as it would be processed as "Flat Mail". Well, of course, there are some type of a system where you can plug in the weight and it will tell you.