Physical rolls, not marketing labels
Enter the dimensions of one physical roll. The optional pack field says how many physical rolls are actually included in a sale unit; do not guess from “single” or “double” alone.
A strip-based method
For one wall, divide its width by the roll width and round up to full strips. Add your trim to the wall height. Straight-match cuts round up to a whole pattern repeat, and this conservative model reserves one repeat at the start of each roll.
Important exclusions
We do not subtract doors or windows, reuse offcuts or pool strips around corners. Half-drop, offset matches, murals and precut panel systems need a product-specific plan and are not supported.
For example, a 120-inch wall with 20.5-inch-wide paper requires six full-width strips. With 100-inch cuts and a 396-inch physical roll, three strips fit per roll, requiring two rolls.
Manufacturer context: one wallpaper maker describes a single roll as typically 21 in × 16.5 ft and a double roll as 21 in × 33 ft, adds that “there can be variations in these measurements depending on the manufacturer”, and sells its own paper as 24 in × 33 ft (Milton & King, single vs double roll). The same maker’s measuring guide says not to subtract windows and doors and excludes murals and panel designs (Milton & King, how many rolls) — the same boundaries this calculator keeps. The roll-start reserve for straight match is this project’s stated modeling choice, not a universal manufacturer rule.
Not sure what to measure? Read how to measure a room for paint, wallpaper and flooring.
What this page decides: how many full-height strips your wall takes, how many of those strips come off one physical roll, and how many rolls or packs that makes. What it does not decide: the roll size or the match printed on the product page, and it will not estimate a half-drop or offset pattern at all. Under every result it states its own assumptions, including that it reserves one repeat at the start of each roll and performs no offcut reuse or corner pooling.
Walls worked through with this calculator
Three worked examples on the fields above, including the one case this tool refuses to count.
- Why a 108-square-foot wall is not two rolls — a 12-by-9 wall divided by the 65 square feet on the label looks like two rolls; counted by the strip it is three on two of the three real rolls, and a two-roll pack makes it four.
- One accent wall, two rolls — a 10-by-8 accent wall takes two 24-inch rolls whether the repeat is 8 inches or 19, and the three places the count jumps to three.
- The calculator refused my half-drop — same wall, same roll, same repeat: switch the match to half-drop and this page prints “No valid list yet” instead of a roll count, and why that refusal is deliberate.