How To Calculate How Much Wallpaper You Need

Written by Materials | Translated by José Tomás Franco
Published on August 13, 2019

Once the construction of an architecture project is finished, it's time to install the claddings that will make up the visible faces of the interior spaces. Wallpaper –an efficient way to bring color and design into rooms – is generally specified according to the square meters we want to cover, so we must start by calculating the area of each surface with great precision.

This task can be easy on clear walls with standard dimensions, but it can generate mishaps or unnecessary expenses in more complex designs. We present some tips to make an estimate as accurate and efficient as possible.

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Wallpaper with Monochromatic Designs or Easy-to-fit Patterns

Before any calculation, you should know the format of the paper you want to use. Some are sold in rolls with predefined dimensions, while others are manufactured to order, according to the specific dimensions of each project.

When choosing simple designs, the first step in determining the amount of paper needed on a surface is to calculate its area. If we talk about a complete wall, basically you must multiply its height to the ceiling by its total length, and then subtract the areas that will not be covered: doors, windows, moldings, electrical outlets, built-in-furniture and/or artifacts, among others. It's important to remember that when installing the papers they must overlap a few millimeters.

Ichijoji House / atelier Luke. Image © atelier Luke

On a wall, 2.50 meters high and 3.00 meters long, the area to be covered is 7.50 m2. If you have a door of 2.00 meters high and 70 centimeters, you must subtract 1.40 m2 (7.50 – 1.40 = 6.10 m2). The operation must be repeated with the width and length of the paper. A roll of 0.70 meters wide and 5.00 meters long allows a covering of 3.5 m2. By dividing the area of the wall by the area of the paper roll (6.10 m2 / 3.50 m2), we observe that 1.75 rolls are needed to cover the entire surface, with a portion of paper left over when buying the 2 required rolls.

When you want to cover the entire height of the walls and avoid the appearance of excessive "patches," it's possible to calculate the number of rolls that will be needed to cover the total height of the wall, dividing the length of the paper by the height of the wall. In the previous example, 1 roll of paper allows us to cover the height of the wall 2 times (5.00 / 2.50 = 2), that is, a width of 1.4 meters if we consider that the width of the paper is 0.70 meters (0.7 x 2 = 1.40 meters). With two rolls we would cover almost the entire surface, using the excess paper to cover the missing areas and to be creatively incorporated into furniture or smaller elements of the same room.

Snow Hotel / 1990 uao + Archigroup MA. Image © Carola Ripamonti

Complex Wallpapers with Hard-to-fit Patterns

When choosing more complex wallpapers, it's important to consider that although we buy more paper than necessary, the excess paper may not correspond to the missing section. In these cases, we recommend making installation tests on the surface elevations to be intervened, for example, through photomontages. In this way, we can predict how the paper will look once installed and calculate exactly how many rolls we need and how much paper will be leftover for other uses.

In custom-made wallcoverings, the amount of paper to be used can be estimated by measuring the repetition of the paper design pattern. Suppose that in the paper roll of the previous example, the design is repeated vertically every 0.7 meters. If we divide the height of the wall by the measure of repetition of the design (2.50 m / 0.7 m = 3.6), the design will be repeated 3.6 times for each strip located on the wall. If we round this number to 4, to make sure we have all the "pieces of the puzzle," we would need the pattern repeated 20 times to cover the entire wall. However, it's possible to subtract 3 "pieces" when considering the presence of the door. In total, we need the design repeated 17 times, that is, 11.90 meters long of wallpaper.

Wallpaper is certainly a good resource to define the aesthetics of a room, highlighting the best features of the designed space. Below, review some projects that have applied wallpaper in favor of space and architecture.