First, you need to determine the length and width of the wall/surface area you are covering in feet. Calculate the total square footage of your surface by multiplying the length of your wall by the width of your wall.
For example, if the height of your wall is 8 ft. and the width of your wall is 10 ft, you would do the following:
8 ft. x 10 ft. = 80 square ft.
Each wallpaper style should have the dimensions for each roll, so you would use the following formula to decide how many rolls you need to purchase:
[Total square footage of your wall] / [total square footage of one wallpaper roll] = # of rolls required.
Keep in mind that you MUST round up to have enough wallpaper. For example, if your calculation came out to 1.42, you must round up and purchase 2 rolls of wallpaper to have enough material.