960 square feet.
I believe you are asking about a "seam allowance". ("Inseam" is the measurement of the seam that runs down the inside of your leg -- for example, men's pants that are labeled 32x30 means the waist is 32 inches and the inseam (from crotch to hem on the inside of the leg) is 30 inches.) To answer your question, all commercially printed patterns include a seam allowance. They are designed for you to cut on the outside solid line, and then stitch the pieces together with the seam width indicated on the pattern piece (usually 5/8 inch).