How to calculate the number of wallpaper rolls I need?
Installing wallpaper is quite an easy task when considering the impact it brings to your interior. However, before you embark on this project that will transform your room, it is essential to know how many rolls of wallpaper you will need to cover the walls of your space.
In this article, we’ll provide you with the keys to accurately calculate the number of wallpaper rolls required in order to save your time and money. So, grab your tape measure, get your calculators ready, and let’s get started!
Measuring the Surface Area of Your Room
First of all, you need to know the total surface area of the walls you want to cover with wallpaper.
Calculating the Perimeter of the Room
Start by measuring the height and length of each wall, then note them down.
- Calculate the perimeter of the room by adding the lengths of the various walls. The perimeter (P) is obtained using the formula: P = L1 + L2 + L3 …, where Li represents the length of each wall.
- Then, measure the height (H) of the room. This value will be used to determine the number of strips in a roll of wallpaper.
It’s also wise to add a few extra centimeters to each measurement to account for margins of error during cutting, pattern matching, or any uncertainty about the exact ceiling height.
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Subtracting the Surfaces of Doors and Windows
To be more precise in your calculations, subtract the area occupied by the different openings (doors and windows) in your room. Here’s how:
- Measure the width (w) and height (h) of each door and window and note them down;
- Calculate the area of each opening by multiplying its width by its height: A = w x h;
- Add up all these areas and subtract them from the initial total perimeter to get the net surface area to be covered with wallpaper.
Considering the Dimensions of the Wallpaper
To determine how many rolls of wallpaper you’ll need, you must consider the characteristics of the wallpaper itself:
- The width of the wallpaper roll: The standard width of a wallpaper roll is generally around 53 cm. However, depending on the selected wallpaper models, available widths may vary. Therefore, you should refer to the manufacturer’s specifications.
- The length of the wallpaper roll: The standard length of a wallpaper roll is usually 10 meters, or about 33 feet. Some new models also offer rolls that are 52 cm wide and up to 3 meters long, providing even more options for wall covering. Note that the presence of a repeat pattern can affect your calculation and may require purchasing extra rolls.
Calculating the Number of Wallpaper Rolls You Need
Once the dimensions of your room and the wallpaper have been considered, it’s time to estimate the number of strips as well as the number of rolls needed to cover your surface.
Calculating the Number of Strips in a Wallpaper Roll
To determine how many strips (or lengths) are in a roll of wallpaper, simply divide the total length of the roll by the height of each strip:
Number of strips = Roll length / Strip height
Don’t forget to include the margins of error that you added at the beginning of your measurements.
Determining the Number of Rolls to Buy
With the number of strips in a roll and the total surface area to cover, you can now determine how many rolls will be needed for your room:
- Divide the net surface area (taking into account the openings) by the width of the wallpaper to get the total number of strips needed: Total number of strips = Net surface area / Wallpaper width;
- Finally, divide this total number of strips by the number of strips per roll: Number of rolls = Total number of strips / Number of strips per roll.
- Always round up the result to the nearest whole number.
Example: Let’s say you have a net surface area of 20 square meters to cover with a wallpaper that is 53 cm wide and 10 meters long. The total number of strips would be 37.74 (20/0.53). Considering that there are 5.26 strips in a roll (10/1.9), you would need approximately 7.17 rolls, or 8 rolls.
You now know how to calculate the number of wallpaper rolls you need for your interior decorating project. It’s time to choose your favorite design and start applying it!
