A traditional Japanese futon called a shikibuton is a sleeping pad that has been used in Japan for centuries. It's traditionally made of 100 percent cotton padding and has a fabric cover that is laid on a tatami (straw) mat for sleeping. Normally stored away at night, the Japanese futon is portable and simple to make.
Decide on the size of the futon you want and make note of the dimensions. Typical twin futon measurements are 39 inches wide and 75 inches long; full size are 54 inches wide and 75 inches long and queen are 60 inches by 80 inches long.
Go to an upholstery supply store to purchase the cotton, zipper and the fabric for the futon cover. Traditional Japanese futons are made from 100 percent cotton and you'll roughly need three to four layers depending on the firmness you prefer.
Cut the fabric according your desired measurements adding an additional 1cm for an easy fit. Turn the fabric inside out and sew the three sides together. Sew a zipper on the open side and turn the fabric inside out, thereby creating the finished futon cover.
Lay out the cotton padding. An adhesive, such as rubber glue, can be used to adhere the layers together but that's optional.
Insert the cotton padding into the fabric cover. Gently push the cotton into the corners for a smooth and even surface if necessary.