If you're wondering how much wallpaper you need to cover the walls of your bedroom, this wallpaper calculator might be right up your alley. It will determine the number of wallpaper rolls that you need to buy. It takes into account multiple factors, such as the repeat of the pattern or custom wall openings.
If you're unsure whether you want to use wallpaper or paint, you can always check out our paint calculator.
How much wallpaper do I need?
Our wallpaper calculator requires you to input some data first. It includes the following values:
Room dimensions: you need to type in the room's length, width, and height. If your room has a different shape than a rectangular cuboid, you can also input the surface area directly (obtain it with our surface area calculator). We recommend that you measure the height of your room anyhow if you want to include pattern repeat into the calculations.
Doors: you can leave the default dimensions of doors or customize them. Once you type in the number of doors, the wallpaper calculator will find their area automatically.
Windows: again, you can choose the default dimensions or type in custom ones. If you have windows of different sizes in your room, you can also calculate the total area manually and input this value into the appropriate box.
Wallpaper specifications: these include values such as the cost of one wallpaper roll, its length, width, and the paper repeat (measured vertically). You can find all of these values on the wallpaper packaging.
Once you type in all of these values, our wallpaper calculator will find the following for you:
- Adjusted height: this is the actual length of wallpaper you will need to use per stripe to account for the pattern repeat.
- Adjusted room area: takes into consideration both the pattern repeat and openings.
- Number of rolls: the total number of wallpaper rolls you need to buy. The calculator always rounds this number up (learn about different rounding modes in our rounding calculator).
- Total cost: the total amount of money you need to pay for your wallpaper.
How accurate is the result?
Even though the result is most accurate when it comes to the pattern repeat, you should add 10% of additional wallpaper to account for complicated fittings or for trimming. If the shape of your room is very complex, you should consult your decorator prior to the wallpaper purchase.
How do I calculate the amount of wallpaper I need for a room?
To calculate the amount of wallpaper you need for a room, follow these easy steps:
- Calculate the gross surface of the room. For a rectangular room with width
l, and height
h, the area is:
A = 2 × (w + l) × h
- Subtract the surface of the eventual doors and windows.
- Divide the result by the surface area of a wallpaper roll to find the number of rolls. Approximate to the higher integer if your result is a decimal point number.
How do I adjust the number of wallpaper rolls to the pattern repeat?
If you consider the pattern repeat of your wallpaper (the height of your pattern), adjust the number of needed rolls with these steps:
- Calculate the effective height of the room
h = ceil(room height/pattern height) × pattern height
ceilrounds up the result of the division.
- Divide the net area of your room by the true height, then multiply by the effective height.
- Divide the result by the length times the height times the width of the wallpaper roll.
How many rolls of 6 × 1.5 m wallpaper do I need for a 28 m² room?
4 rolls. Say that your room has a surface area of
28 m² to cover in wallpaper. If your roll is
1.5 meters tall and
6 meters long, you can find the number of rolls with the following formula:
N = A/(w × l) = 28 m²/(1.5 m × 6 m) = 3.111...
Since we can't buy a tenth of a roll, we need to round up the result: we find that
N = 4.
What is the wallpaper pattern repeat?
The wallpaper pattern repeat is the distance between two neighboring repeating elements of your desired wallpaper. The pattern repeat matters, as it determines how much waste you will produce in your project: the higher the pattern repeat, the greater the waste, as in order to match two adjacent patterns, you may have to cut strips as high as the repeat itself.