How many rolls of wallpaper do I need?

Wallpaper is not sold by area, it is sold by the roll, and a roll only yields whole drops that fit your ceiling height with the pattern matched. That is why the roll count is often well above what dividing wall area by roll area would suggest: offcuts from the top of one drop rarely match the bottom of the next.

Room perimeter (ft)

2 x (length + width), minus wide openings if you like.

Ceiling height (ft)

Roll width (in)

Roll length (ft)

US double rolls are usually 33 ft.

Pattern repeat (in)

0 for a plain or random-match paper.

Rolls needed

8rolls

Strips needed 29 stripsStrips per roll 4 strips

Assumes straight-match patterns and a uniform ceiling height. Half-drop matches, borders and stairwells need a higher count, and a decorator will always order a spare roll.

The calculation is two steps. First, how many strips the room needs: perimeter divided by the roll width, rounded up, because a partial strip is still a strip. Second, how many strips fit in one roll: roll length divided by the drop, where the drop is ceiling height plus any pattern repeat that has to be wasted to align the pattern.

A large repeat is expensive. A 12 inch repeat on a 33 ft roll at 8 ft ceiling leaves only 3 usable strips instead of 4, which turns 8 rolls into 10 for the same room. If the paper is a bold pattern with a 24 inch repeat, expect to buy 25 to 30 percent more than the plain-paper figure.

How the calculation works

Strip width = roll width in inches / 12. Strips needed = ceil(perimeter / strip width). Strips per roll = floor((roll length - drop allowance) / ceiling height), where the drop allowance is the pattern repeat added to the height.

Rolls = ceil(strips needed / strips per roll). Rounding up at both stages is what makes the answer realistic rather than optimistic.

• Walls are full height with no openings deducted; deduct very large openings such as a full-height glass wall, but not ordinary doors and windows, since paper is cut around them and the offcuts rarely help.
• Ceiling height is uniform; a stairwell or vaulted room needs the maximum height, since every strip must reach the lowest point of the ceiling.
• The pattern repeat is the figure printed on the roll label, and matching is by straight match rather than a half-drop; half-drop patterns waste slightly more.
• Lining paper, adhesive and any border are not included.

Sources: US double roll: 20.5 in x 33 ft, about 56 sq ft (wallcovering industry standard); Pattern repeat figures are printed on the roll label by the manufacturer

Worked examples

Questions

How many rolls of wallpaper for a 12 x 12 room?

Eight rolls of standard 20.5 in x 33 ft paper at an 8 ft ceiling, if the pattern has no repeat. With a 12 in repeat it is ten.

What is a double roll?

The standard US unit: 20.5 in wide by 33 ft long, covering about 56 sq ft. It is called a double roll because it used to be sold as two single rolls.

How much extra should I allow for pattern matching?

Enough for one extra drop per roll at minimum. A 12 in repeat typically costs 20-25 percent more paper; a 24 in repeat can cost 30 percent or more.

Should I deduct doors and windows?

Usually not. Paper is cut around them, and the offcut above a door is rarely long enough to use. Deduct only floor-to-ceiling glass.

Do I need to add for waste?

The rounding in this method already accounts for it. Buy one spare roll if the paper is from a dye lot that may not repeat.

Related calculators

Written and maintained by Sam Winters. Last updated 2026-11-04. Every figure is computed in your browser; nothing you enter is sent anywhere. Found an error? Tell me — accuracy reports get fixed first.