Wallpaper Calculator
US single or double rolls, openings, reserve and cost.
How it works
Wallpaper is counted in strips, not in square metres. Work out how many full strips a roll yields — roll length divided by the height of one strip — then how many strips the perimeter needs. Rounding down on the first division and up on the second is what makes the answer correct.
The pattern repeat is what wastes paper. If the design repeats every 64 cm, each strip must be cut to the next whole multiple of that, so a 2.7 m wall can require a 3.2 m strip. A plain paper with no repeat wastes almost nothing, which is why it works out considerably cheaper than the roll price suggests.
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How the Wallpaper Calculator works
This US wallpaper calculator counts complete strips and full rolls, supports common single and double-roll dimensions, subtracts large openings when requested and prices the complete order including reserve rolls.
Double roll describes length, not a wider sheet
A common US double-roll preset is 20.5 in wide by 33 ft long; the single-roll equivalent is 20.5 in by 16.5 ft. Retail packaging and terminology vary, so enter the exact width and total length printed on the roll being purchased.
The strip calculation rounds in two directions: whole strips per roll round down, while strips required around the room round up. Area-only estimates miss both cuts and commonly understate the order.
Openings, pattern repeat and reserve
Doors and windows are converted into an equivalent width at the entered wall height. Leave openings at zero for a conservative order when offcuts above and below them cannot be reused.
Patterned paper is cut to the next full repeat. Add an unopened reserve roll when future repairs or dye-lot matching matter; the calculator includes it in both spare strips and cost.
FAQ
How many 20.5 in × 33 ft rolls cover a 16 × 13 ft room? expand_more
At an 8 ft wall height with 4 in trim and no repeat, the room needs 34 strips. A 33 ft roll yields three full strips, so the base order is 12 double rolls with two strips left over.
Should windows and doors be subtracted? expand_more
Subtract large openings only when the saved full-width strips can realistically be used elsewhere. Leaving the field at zero gives the safer order for typical doors and windows.