How do I calculate how many rolls of wallpaper I need?

Measure the room perimeter and wall height, choose the roll size, add any pattern repeat, then divide the required strips by the strips you can cut from one roll. The calculator does that and rounds the purchase up to whole rolls.

What is wallpaper pattern repeat?

Pattern repeat is the vertical distance before the design repeats. It can make each cut strip longer than the wall height, which increases waste and roll count.

Do I subtract windows and doors?

The calculator subtracts typical openings from net wall area and paste estimate, but it does not reduce strip count. You still need wallpaper around openings and above them.

How many rolls are in a US double roll?

Wallpaper is often sold as a double roll in the US. The calculator treats each purchased roll by its actual width and length, such as 20.5 in by 33 ft.

Should I buy an extra roll?

Often yes, especially for patterns, drop match, older walls, or future repairs. Extra material should come from the same dye lot.

Can I use this for a mural?

No. Murals and panel wallpapers usually require the manufacturer's panel layout rather than a roll-count estimate.

Wallpaper Calculator

Estimate wallpaper rolls for a room using wall dimensions, US roll sizes, pattern repeat, doors, windows, and waste.

Room dimensions, ft

Length

Width

Wall height

Wallpaper roll

Roll width, in

Roll length, ft

Pattern repeat, in

Doors

Windows

Trim allowance, in/strip

Price per roll, $

Estimated purchase

9 rolls

Strip layout around the room

Strips needed: 26 · strips per roll: 3

Perimeter

44 ft

Wall area

352 sq ft

After openings

301 sq ft

Strip length

8.33 ft

Roll area bought

507.38 sq ft

Estimated waste

206.38 sq ft · 68.56%

Paste estimate

2 lb

Strips per roll

Buy from the same dye lot when possible. Pattern match, wall condition, and room geometry can change the final roll count.

How the wallpaper calculator estimates rolls

This wallpaper calculator estimates rolls from full vertical strips, not from wall area alone. That better matches how wallpaper is purchased and cut: every strip uses the full wall height plus trim allowance, and the final order is rounded up to whole rolls.

Enter room length, width, and wall height in feet.
Choose a common US double roll preset or enter roll width and roll length manually.
Add pattern repeat and trim allowance so each strip can be rounded to a usable cut length.
Enter doors and windows for net wall area and paste estimate.
Add a price per roll if you want a quick material cost estimate.

P = 2 \cdot (L + W)

P is room perimeter, L is room length, and W is room width.

N_{s t r i p} = ⌈ \frac{P}{W _{r o l l}} ⌉

N strip is strips needed, P is perimeter, and W roll is roll width.

N_{p er r o l l} = ⌊ \frac{L _{r o l l}}{L _{s t r i p}} ⌋

N per roll is strips from one roll, L roll is roll length, and L strip is one strip length after trim and repeat.

N_{r o l l} = ⌈ \frac{N _{s t r i p}}{N _{p er r o l l}} ⌉

N roll is rolls to purchase, N strip is strips needed, and N per roll is strips from one roll.

Order all rolls from the same dye lot when possible. A spare roll is often useful for matching, trimming mistakes, and future repairs.

Pattern repeat and match type

Pattern repeat is the vertical distance before a wallpaper design repeats. If the label lists a repeat, the calculator rounds each strip up to a full repeat interval, which can increase waste.

Wallpaper type	Input	Effect on rolls
Solid or random match	0 in	Strip length equals wall height plus trim allowance
Straight match	Repeat from label	Each strip is rounded up to the repeat
Drop match	Repeat from label	Use the result as a purchase estimate and consider extra reserve
Large-scale print	Actual repeat	Usually needs more waste allowance

If the label gives repeat in centimeters, convert it to inches before entering it. A 64 cm repeat is about 25.2 in.

Common roll sizes in the US

Roll type	Typical width	Typical length
US double roll	20.5 in	33 ft
Wide US double roll	27 in	27 ft
Metric roll sold in the US	21 in	33 ft
Commercial wallcovering	36 in	33 ft or more

Doors, windows, and waste

The tool uses common opening allowances: one door reduces net wall area by 21 sq ft and one window by 15 sq ft. Openings affect net area and paste estimate, while strip count still follows the room perimeter.

Opening limitation

Doors and windows do not reduce the strip count in this model. Wallpaper still has to be cut around openings, above openings, and at edges where matching matters.

Input	How it is used
Doors	21 sq ft each for net area
Windows	15 sq ft each for net area
Trim allowance	Added to each strip before pattern repeat rounding
Paste estimate	Estimated from net wall area

For bay windows, tall doors, alcoves, and uneven walls, measure each wall section and keep an extra reserve.

Estimate limits

The calculator is designed for a rectangular room with one wall height. It is a buying estimate, not a replacement for a detailed wall-by-wall layout for complex rooms.

Scenario	What to do
Different wall heights	Estimate sections separately and use extra reserve
Alcoves, columns, or angled walls	Break the room into wall sections and verify the layout on site
Strip length longer than roll length	Check height, repeat, trim allowance, or choose a longer roll
Murals and panels	Use the manufacturer's panel layout instead of a roll calculator

Manufacturer labels and installation guides should be treated as the final source for roll dimensions, repeat, match type, and recommended extra material.

Frequently Asked Questions

Sources and References

Calculations are based on the listed reference sources. Links open in a new tab.

Updated: June 2, 2026

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