# How To Calculate Wallpaper Measurements

Wallpaper installation can be tricky, especially when it comes to determining exactly how many rolls of wallpaper you need. While some people are satisfied with simply guessing the number of rolls, you can be more efficient and cost effective by computing the wallpaper measurements. Here’s how.

**Measure**. Begin by measuring the height, length, and the width of the wall that you will be installing the wallpaper on. Make sure that your measurements are accurate, and if you must, take the measurements twice just to be sure.

**Square footage**. Next, compute for the square footage of the wall. The formula that is used to do this is ( L + L + W + H) x 10. This means that the length will be added twice to the width and the height of the wall, and the sum resulting from this will then be multiplied to ten. This means that if you have a wall that is nine feet in length, ten feet wide, and with a height of nine feet, you will have a that is ( 9 + 9 + 10 + 9 ) x 10, which will be equal to 370 square feet.

**Subtract the doors**. Unless the wall where you will install the wallpaper is blank, you will also have to subtract the doors and the windows from the square footage of the wall. This can be done by taking the square footage of the doors and windows, which are easier to determine compared to the walls. You will simply need to measure the windows and doors in terms of length and width. Multiply the length and the width with each other and subtract these from the wall’s square footage, and you should arrive at the area for the rest of the wall.

**Divide**. Next, scout for wallpapers and determine how much square footage is available in each roll. Keep in mind that different wallpapers will have different square footages. Design centers will usually have a specific square footage per roll, while designer wallpapers from specialty shops will have their own measurements. Consult the design center clerks or check the labels on the packaging first, to determine the square footage per roll of wallpaper. Once this is done, the next step is to divide the wall’s square footage by the roll of wallpaper. This will be the number of wallpaper rolls that you will need.

**Add the pattern length**. However, the patterns and prints on the wallpaper will also determine whether you should add some excess wallpaper to allow you to match the edges of the wallpaper design as you move from one roll to the other. To do this, you should add 18 inches at least to each roll of wallpaper. This means that a wallpaper roll that measures eight feet and which has a large design pastern should be bought at a length of 9.5 feet.

Once you have the amount of wallpaper rolls that you need, you can install the wallpaper without having to worry about ending up short on wallpaper or wasting excess wallpaper.