Calculate how many wallpaper rolls you need from your wall and roll measurements. This free calculator counts full strips and allows for pattern matching, seam overlap and trimming.
How to use itHow the calculation worksCommon questions
How to use the wallpaper calculator
- Choose your wall units and enter each wall's width and height. Add more walls if you are using the same wallpaper throughout.
- Enter the usable width and full length of one physical roll. Width and length can use different units.
- Choose free match, straight match or half-drop. For a matching pattern, enter the vertical repeat from the label.
- Open the extra settings to check seams, trim and spare rolls. Only select overlap when your product requires it.
- Select Calculate rolls. Review the roll total, strips for each wall and the cutting plan before ordering.
Changing a unit converts the numbers already entered. One foot is 12 inches, so 8 ft 6 in should be entered as 8.5 ft or 102 in. Changes to measurements clear the previous result so you do not mistake it for an updated estimate.
Measure the wall and check the roll label
Measure the area that will actually be papered, from its top edge to its bottom edge. If wallpaper stops above a dado rail or skirting board, measure only to that edge. Check height and width in several places and use the largest measurements.
Enter each wall separately. The calculator keeps enough full-width strips for each wall rather than assuming a narrow offcut from one wall can cover the next. For a sloping ceiling, the tallest height gives a cautious rectangular estimate. A shaped cutting plan can use less material.
Keep windows and doors inside your wall measurements. Subtracting their area can suggest fewer rolls even when you still need full strips to match the pattern above, below and beside the opening. Large openings may allow savings, but these need a separate measured layout.
Read the size of the physical roll, not only its advertised area. Single roll, double roll and bolt are sales terms, not universal dimensions. If a shop prices by the single roll but sends one continuous double roll, enter that complete roll's length. The result refers to those physical rolls. Check how many ordering units or packs they represent at checkout.
How the calculation works
For butt joints, strips for one wall = wall width including side allowances ÷ usable roll width, rounded up. Each strip must be long enough for the wall height plus the top and bottom trim.
For overlap, the first strip covers its full width. Every following strip covers the roll width minus the overlap. The calculator finds the first whole number of strips that covers the wall. If the width on the label is already the installed coverage width, choose that option. The overlap is then not deducted again.
For free-match wallpaper, strips can be cut one after another. Straight-match strips must start at matching points in the pattern. Half-drop strips alternate between two starting positions, half a vertical repeat apart. The plan keeps those positions when placing strips on rolls.
The calculator places longer strips first and uses remaining roll lengths where another complete strip fits. This is a practical cutting estimate. It does not claim the smallest possible order for every layout. It does not join short pieces to make a full-height strip or assume that narrow side offcuts can be reused.
For matching patterns, the default setting reserves one repeat at the start of every roll because its starting pattern position may be unknown. This is an allowance, not an instruction to cut off exactly that much. Match the actual pattern before cutting. The diagram shows planned material use; its numbered strips must still be hung in wall order.
The estimate assumes rectangular walls, vertical hanging, one wallpaper design and one roll size. Half-drop starts again with strip A on each wall. If a pattern must continue around corners, or the label specifies a quarter-drop, multiple-roll A/B system or reverse hanging, ask the supplier for a product-specific plan.
A simple wallpaper calculation example
Suppose your wall is 300 cm wide and 240 cm high. Your free-match wallpaper is 53 cm wide and 10.05 m long. You allow 5 cm at the top and 5 cm at the bottom, with butt joints and no extra side allowance.
- 300 ÷ 53 = 5.66, so the wall needs 6 strips.
- 240 + 5 + 5 = 250 cm per strip.
- A 1,005 cm roll gives 4 complete strips of 250 cm.
- Six strips need 2 physical rolls. The first supplies 4 strips and the second supplies 2.
This is why area alone can mislead. A different wall height or pattern repeat can reduce the number of complete strips from each roll, even when the total wall area is similar. Select Load example to try these measurements in the calculator.
Common questions
Does this work for peel-and-stick wallpaper?
Yes, for repeat-pattern material supplied in rolls that can be cut into strips. Enter its actual dimensions and specified seam method. Custom murals with numbered panels need their own panel layout. Do not treat their panels as interchangeable rolls.
Should I choose overlap or butt joints?
Follow the product instructions. Butt joints bring the edges together. An overlap places one edge over the previous strip. Changing the seam method can affect the finished width and pattern. Our peel-and-stick wallpaper installation guide explains panel alignment.
What is the vertical pattern repeat?
It is the distance along the roll between two identical points in the repeating design. It is separate from the roll width and the pattern match type. Use the label or ask the supplier if either detail is missing.
Should I add another 10 percent for waste?
The plan already includes the trim, pattern alignment and unusable roll ends shown in the result. Adding a percentage automatically would count some losses twice. Use Spare whole rolls if you want extra material for damage or future repairs. Choose an amount that suits the job and order matching batch numbers where applicable.
Why can the result be higher than an area calculator?
Wallpaper is installed in strips. A leftover piece may have enough area but still be too short, too narrow or at the wrong pattern position. This calculator only counts complete strips that fit the selected roll.
Can I use the diagram as an exact cutting instruction?
Use it to plan and label the strips. Check every wall, the pattern, material condition and manufacturer instructions before making cuts. Roll-start reserves are budgeting allowances. The actual first cut depends on where the printed design starts.
Plan the rest of your wall project
Explore wallpaper and wall murals after checking your measurements. For custom artwork, read our wall mural measuring guide. For a smaller decorative design, use the wall decal size calculator.
Further reading
Manufacturer references explain why product details matter: Graham & Brown on pattern repeats and matching, Spoonflower on measuring and ordering rolls, and Brewster on wallpaper properties and match types. The instructions supplied with your own wallpaper take priority.
