Wallpaper can add color, pattern, and texture to make a room feel inviting and comfortable. If you are planning to install wallpaper at home, accurately calculating your paper requirements will help you buy the right amount of wallpaper. By knowing the surface area of the wall and measuring the pattern of wallpaper you want, you can easily estimate the number of rolls of paper you will need. When you're done counting, you'll be ready to install it!
Step
Part 1 of 2: Measuring the Surface Area of a Wall
Step 1. Measure the length of each wall on which you will apply the paper
Place the end of the tape measure against one end of the wall and pull it over the other. Once you get to the other end, write down the measurement results. Round to the nearest number above it so that you have a little bit to spare when calculating. Keep measuring the length of each wall you are going to apply the wallpaper to and writing down the results so you don't forget.
- For example, if the length of the wall is 303.53 cm, round it to 304 cm.
- If the room is rectangular, you'll only need to measure two walls because the opposite walls will be the same length.
Step 2. Find the height of the wall on which you will apply the wallpaper
Find the highest point and start measuring from that point so that the wallpaper you buy is not lacking. Place the end of the tape measure against the wall and extend it toward the ceiling. Keep pulling until the meter reaches the floor. Round up the measurement results so that there is excess wallpaper.
For example, if the height of the wall is 244.25 cm, round it to 245 cm
Step 3. Convert measurements to feet or meters
Wallpaper is usually measured in square meters. So you have to change the measurement result. If you're measuring length and width using inches, divide each measurement by 12 to convert it to feet. If you're using centimeters, divide the measurement by 100 to convert it to meters.
For example, if your wall is 300 cm (120 inches), divide by 100 for centimeters or 12 for inches to get 3 m (10 feet)
Step 4. Multiply the total length by the height of the wall to find the surface area
Add up the entire length of the walls to find the total length. Multiply the total perimeter by the height of the walls to get the total surface area of the room. Use a calculator if you need one so you can calculate exactly how much area you will cover.
- For example, if the total length is 15 m (48 ft) and the wall height is 3 m (10 ft), the total surface area is (15)(3).
- Multiply the numbers: (15)(3) = 45 square meters.
Tip:
You do not need to reduce the area of this area by the area of the door or window because excess paper is better than paper shortage.
Step 5. Calculate the sloped wall if any
If your walls are angled to the ceiling or triangular at the top, you'll need to calculate differently. Find the length from one end of the triangle to the other to measure the base. After that, measure the height from the top of the triangle to the bottom of the triangle. Multiply the length of the base by the height of the triangle then divide by two to find the surface area.
- For example, if the base is 3 m (10 ft) long and 1.5 m (5 ft) high, the surface area is (3)(1, 5)/2.
- Simplify the equation: 4.5/2 = 2.3 square meters
Part 2 of 2: Determining the Number of Wallpaper Rolls
Step 1. Measure the distance between the repeating patterns on your wallpaper
Look at the end of the wallpaper roll. You should find two identical parts of the pattern. Hold the tip of the tape measure at one point and continue pulling the tape measure until the pattern points start to repeat. Write down the measurements so you can estimate how many rolls of wallpaper you will need.
- For example, if the wallpaper has a floral pattern, measure the vertical distance between the center of one flower and the center of another identical flower.
- If the wallpaper has a random or non-repeating pattern, you don't need to measure.
- Often times, repeating wallpaper patterns are printed on the packaging.
Step 2. Calculate the amount of wallpaper that can be used per roll based on the pattern measurement results
Although the total surface area of the wallpaper is written on the packaging, the amount of paper that can be used varies depending on the pattern and how much you need to cut to make the pattern appear continuous. Once you've measured the distance between identical patterns, use the formula below to calculate how much wallpaper you can use per roll:
- If the spacing between identical patterns is 0-15 cm (0-6 inches), the acceptable wallpaper is 2.3 square meters (25 square feet).
- If the spacing between patterns is 18-30 cm (7-12 inches), 2 square meters (23 square feet) of wallpaper can be used.
- If the spacing between patterns is 33-46 cm (13-18 inches), you can use 1.9 square meters (20 square feet) of wallpaper.
- If the spacing between patterns is 48-58 cm (19-23 inches), you can use 1.4 square meters (15 square feet) of wallpaper.
- The width of the wallpaper may vary, but the surface area covered by the wallpaper remains the same.
Step 3. Divide the total wall surface area by the amount of wallpaper that can be used per roll
Use a calculator so you can calculate easily and round up so you have enough wallpaper. If you wish, add one more roller just in case you make a mistake or have to make repairs in the future.
- For example, if the total surface area is 45 square meters (480 square feet) and each roll provides 2.3 square meters of wallpaper, you would need 45/2, 3 = 19, 6.
- Round up. So you need 20 rollers to cover the walls.
- Wallpaper is sold as a single layer or in duplicate. For example, according to the previous calculation, you can buy 20 rolls of single-ply wallpaper or 10 rolls of duplicate to cover the same surface area.
Step 4. Add 10-20% just in case
Look at the number of rollers you need based on previous calculations and multiply by 0, 1 or 0, 2 to find 10-20%. Purchase a few extra rollers so you have a spare in case you make a mistake or need to make repairs in the future.
- For example, if you need 20 rollers to cover a wall surface, purchase an additional 2-4 rollers just in case.
- Take your calculations to a wallpaper shop and have them double-check your estimate to make sure you bought enough wallpaper.
Tip:
Make sure you order all wallpapers from the same batch as wallpapers from different batches may have slightly different colors and patterns.
Tips
- There are many wallpaper calculators online that you can use to calculate the amount of wallpaper you need.
- Many wallpaper suppliers can give you an estimate of the need if you bring your wall measurements.
- You don't need to reduce the surface area of the wall by the area of the door or window because excess paper is better than paper shortage.
