So, for example, if your laptop is 15" x 9" x 1", your rectangle measurements are now 15.5" x 9.5". Then add on a half inch to every side—this is called your "seam allowance" where you'll be sewing.

Our laptop sleeve of choice: Crumpler Fug We’ve been looking for a thin laptop sleeve for our MacBook Pro 15-inch (Retina Display) and so far most of the products we’ve tried were surprisingly add to ...