Interior

Wallpaper Calculator: How Many Rolls Do I Need?

Work out rolls from your wall dimensions and pattern repeat — the repeat is what most calculators ignore and what most people run short on.

Your measurements

Room length (ft)

Room width (ft)

Ceiling height (ft)

Roll width (in)20.5 in is the European standard; American rolls are often 27 in.

Roll length (ft)

Pattern repeat (in)0 for a plain or random-match paper. Printed on the roll label.

Doors

Windows

Wallpaper to order

8rolls

29 strips at 4 strips per roll

Wall perimeter: 52 ft
Strips needed20.5 in wide each: 29
Cut length per stripNo pattern repeat: 8.00 ft
Strips per roll: 4

Order every roll in one go and check that the batch (or 'dye lot') number matches. Two batches of the same paper are visibly different on the wall.
Buy one extra roll beyond the calculated number if the pattern is discontinued — future repairs are impossible without it.
This assumes floor-to-ceiling drops on straight walls. Staircases, dormers and sloped ceilings need a strip-by-strip take-off instead.

How this is calculated

The room perimeter is divided by the usable roll width to get the number of vertical strips.
Each strip's cut length is the ceiling height rounded UP to the next whole pattern repeat, because every strip has to start at the same point in the design to match its neighbour.
Roll length divided by cut length gives strips per roll — always rounded down, since a part-strip cannot span a wall.
Doors and windows are only credited once their combined width exceeds a full strip; a strip interrupted by a window still consumes most of a drop.

Quantities are rounded up, because materials are sold in whole units and a second trip costs more than a spare box. Cost figures are typical US ranges and are not a quote — always price against your own supplier.

Frequently asked questions

How many rolls of wallpaper for a 12x12 room?

A 12×12 room with 8 ft ceilings has a 48 ft perimeter. With standard 20.5 in rolls that is 29 strips. A 33 ft roll yields 4 strips at an 8 ft drop with no repeat, so you need about 7 rolls — more if the paper has a large repeat.

What does 'pattern repeat' mean and why does it matter?

The repeat is the vertical distance before the design starts again. Every strip has to begin at the same point in that design, so each cut is rounded up to a whole repeat. A 24 in repeat on an 8 ft wall means cutting 9 ft strips and binning a foot per drop — which can add two rolls to a small room.

Should I buy an extra roll?

Yes, almost always. Batch numbers change, papers get discontinued, and a single damaged strip with no matching stock means repapering the whole wall. One spare roll is cheap insurance.

Know the quantities. Now see the room.

You have the numbers for the job. Upload a photo of the room and see what it looks like finished, in any style, before you buy a single box.

Try the AI room designer

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