If you need a little help with the sewing this visual aid will help - originally done for the knitting needle tidies but the corners are equally applicable here: HOW TO MAKE TIDIESSold :
Wallpaper Coverage Calculator
Based on the dimensions you provide, this calculator will determine the number of custom-length sections of paper you'll need to cover any surface. If the height of your surface varies, input the tallest dimension in order for the pattern to line up correctly.
Enter your dimensions in feet (1 foot is 30.48 cm).