How much wallpaper do I need?
Store-bought wallpaper comes in rolls, while custom and mural wallpaper is printed as panels made for your wall. Here is how to count each one, with worked examples and a free planner.
How many rolls of wallpaper do I need?
First find how many full-height strips one roll gives: divide the roll length by the wall height plus the pattern repeat plus about 4 inches (10 cm) for trimming, and round down. Then divide the wall width by the roll width and round up to get the strips you need. Divide the strips you need by the strips per roll, round up, and buy one extra roll from the same batch.
strips needed = wall width ÷ roll width (round up)
rolls = strips needed ÷ strips per roll (round up), plus 1 spare
How big is a roll of wallpaper?
In the US, wallpaper is often priced per single roll but sold as a double roll of about 20½ inches by 33 feet, which covers about 56 ft². A standard European roll is 0.53 m wide and 10.05 m long, about 5.3 m². Sizes vary between brands, so use the width, length and pattern repeat printed on the label.
Worked example: rolls
- Wall 12 ft wide × 8 ft (96″) high, pattern repeat 21″, US double roll 20½″ × 33 ft (396″).
- Each strip: 96 + 21 + 4 = 121″. 396 ÷ 121 = 3.27, so 3 strips per roll.
- Strips needed: 144 ÷ 20.5 = 7.02, so 8 strips.
- Rolls: 8 ÷ 3 = 2.67, so 3 double rolls, plus 1 spare = 4 double rolls.
- Metric: wall 4 m × 2.5 m, repeat 53 cm, European roll 0.53 × 10.05 m. Strip 250 + 53 + 10 = 313 cm, so 3 strips per roll; 400 ÷ 53 = 7.5, so 8 strips; 8 ÷ 3 rounds up to 3 rolls, plus 1 spare = 4 rolls.
Do I take off windows and doors when counting rolls?
Usually not for a normal window or door, because the leftover pieces are used above and below them and still have to match the pattern. Take off only a wide opening such as a patio door. For a whole room, add the widths of all the walls together first, then count the strips.
How many custom wallpaper panels do I need?
Custom and mural wallpaper is printed as long panels made to fit your wall. Add a little extra to each side of the wall for trimming, often about 5 cm or 2 inches. Subtract the overlap between panels from the roll width to get the useful width of each strip. Divide the wall width plus both trims, minus one overlap, by that useful width, and round up.
panel length = wall height + 2 × trim
Worked example: mural panels
- Wall 4.2 m wide × 2.9 m high. Trim 5 cm each side, overlap 2 cm, roll 106.7 cm (42″).
- (420 + 10 − 2) ÷ (106.7 − 2) = 4.09, so 5 panels.
- Each panel is 106.7 × 300 cm. At 150 ppi that is about 6,300 × 17,700 pixels.
What resolution does a wallpaper mural need?
Wallpaper is seen from a step or two away, so around 100 to 150 pixels per inch at full size usually looks sharp. A small picture saved from the web may only reach a few pixels per inch across a whole wall, which prints blurry. Roomveil checks this for you and tells you how many pixels the picture needs to print sharp.
What about switches and sockets?
Installers usually cut wallpaper around switch plates. For a custom print, Roomveil also shows two other options: a matching sticker printed for the plate so the design runs straight across, or a slim frame in the design's darkest color so the switch looks planned.
Plan it on your wall
Roomveil shows wallpaper on a photo of your wall with windows and doors cut out. For a custom print, it places your picture, lets you add a second picture with colors matched to the first, checks the resolution and lists the panel sizes to send to your print shop.
These are common rules of thumb and code minimums, given for planning. Always check the product label, the maker's instructions and your local building code before you buy or build.