The best way to start is to read my "Wallcovering Types" before you pick out material. Once you select a wallcovering, bring the book home and give me a call.    I will give you a free price estimate and consultation in your home. Then you can order the correct amount of material. If you can't get the book try to get info on the wallpaper: Roll width, length, and pattern repeat in inches. This info is usually available on the company's site. This is really the only way to insure that you don't order too little or too much. Returning unused wallcovering costs you money unnecessarily.     One note on that:   A lot of what is sold online as "wallpaper" nowadays is self adhesive contact paper and is essentially a DIY product of low quality. Also beware of start up companies that print up wallcoverings on a digital printer using inks that will wipe off with a sponge and water. This why I wrote about "Types of Wallpaper"--so if you click on the link above and spend some time getting familiar with what is on the market you can avoid having a bad experience. A good quality wallpaper installed by a pro will be thing of joy and last for years. If you have any questions about anything call me or text me at 843-303-5975 or email me at  jimparodi@gmail.com