Wallpaper Calculator
Calculate how many rolls of wallpaper you need - accounting for pattern repeat and waste.
The wallpaper calculator returns the exact number of rolls you need for any room, with pattern repeat and waste factored in. Enter your room dimensions and tell the calculator your roll type (single, double or Euro) and the pattern repeat size from the wallpaper label. Patterned papers need more material than solid colors because each strip has to line up at the seams - a 12 inch repeat typically adds 20% waste, while a 24 inch repeat adds 30%. The calculator handles this automatically so you do not run short on a job where you cannot get a matching dye lot later.
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Frequently asked questions
A 12x10 room with 8 ft ceilings has about 350 sq ft of paintable wall area. With a 12 in pattern repeat and standard US double rolls (56 sq ft usable), you need 8 rolls. Solid colors with no repeat would need 7. Always buy from the same dye lot - color matching between lots is almost impossible later.
In the US, wallpaper is priced per single roll but typically sold in double rolls. A US double roll = two single rolls = ~56 sq ft usable area. European rolls are sized differently (~30 sq ft each) and are narrower (20.5 in vs the US standard 27 in). Always check the label - manufacturer specs vary.
Pattern repeat is the vertical distance before the design repeats. Each strip has to be cut so the pattern aligns at the seam with the adjacent strip, which wastes material at the top or bottom of each strip. Small repeats (under 6 in) waste 10%; medium (6-12 in) waste 20%; large (12-24 in) waste 30%. Random match patterns have no waste; straight match patterns waste the most.
Yes - always buy at least one extra roll beyond the calculator estimate. Dye lots vary between production runs, so a matching roll bought 6 months later is almost impossible to find. Extra rolls are useful for future repairs from damage, and many retailers accept returns on unopened rolls if you ordered too many.
Measure from the top of the baseboard to the bottom of the ceiling molding (the actual papered surface), not floor to ceiling. Add 4 inches per strip for trim and pattern matching at top and bottom. If you have crown molding and tall baseboards, the wallpaper height is several inches shorter than the floor-to-ceiling measurement.