How many wallpaper panels do I need?
Custom and mural wallpaper is printed as long panels. Work out how many strips cover the wall with overlap and trim, and what size to send the printer. Here is the rule with an example.
How do I work out the number of wallpaper panels?
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
- 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 wallpaper 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 can sharpen small pictures.
What about switches and sockets?
Installers usually cut wallpaper around switch plates. 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 colour so the switch looks planned.
Plan it on your wall
Roomveil places your picture on a photo of your wall with windows and doors cut out, lets you add a second picture with colours matched to the first, 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.