Wallpaper Calculator

Estimate wallpaper rolls for a room

This wallpaper calculator estimates the number of rolls needed to cover a room's walls. Enter the room length and width, wall height, number of matching rooms, door and window sizes, wallpaper roll width and length, pattern repeat, and a waste allowance. The result shows estimated wall area, wallpaper drops, roll count, and an optional material cost.

Wallpaper is installed in vertical strips called drops. The length of each drop depends on the wall height and, for patterned paper, the repeat needed to line up the design. A roll does not always provide the same coverage as its printed area suggests because the cuts must match the pattern and fit the wall height.

Use this estimator to plan a purchase, compare wallpaper products, or check a preliminary quote. It assumes rectangular rooms and even wall height. Alcoves, stairwells, sloped ceilings, chimney breasts, feature walls, complex patterns, and product-specific matching rules need separate measurements and may change the final order.

How to use the wallpaper roll calculator

Measure the inside length and width of each room, then enter the wall height from the finished floor to the ceiling or planned wallpaper stopping point. The calculator estimates wall perimeter as two times length plus width. If more than one room has the same size and opening layout, use the matching room count. Calculate rooms with different sizes separately or enter them one group at a time.

Enter the total door and window widths and their heights. The calculator subtracts those openings from wall run and wall area. If openings differ, you can enter the combined width and combined area only by grouping measurements that share the entered size; for complex layouts, calculate each room separately. Small windows may not save a full wallpaper strip, so keep a realistic waste allowance even when openings are deducted.

Read the wallpaper package or product sheet for roll width and roll length. Enter the pattern repeat if the design must line up vertically. For a plain paper or random-match design, use zero. Add waste for trimming, corners, damaged paper, and pattern matching. An optional price per roll gives a basic material subtotal.

Wallpaper quantity formulas

The calculator uses both wall area and strip layout to estimate rolls. It calculates drops required from the wall run and the roll width. It then estimates how many full drops can be cut from a roll using the wall height and pattern-repeat allowance. The higher of the area-based and drop-based estimates is used before waste, which helps avoid relying on area alone when pattern matching reduces usable length.

• Room perimeter = 2 × (room length + room width)
• Net wall run = room perimeter − widths of openings
• Drop length = wall height, increased to the next pattern repeat when needed
• Drops required = round up (net wall run ÷ wallpaper roll width)
• Drops per roll = round down (roll length ÷ drop length)
• Drop-based rolls = round up (drops required ÷ drops per roll)
• Area-based rolls = round up (net wall area ÷ roll area)
• Order rolls = round up (higher estimate × (1 + waste percentage ÷ 100))

Worked example: wallpaper for a bedroom

Suppose a bedroom is 12 feet long, 10 feet wide, and 8 feet high. The wall perimeter is 2 × (12 + 10), or 44 feet. If the room has one 3-foot-wide door and one 3-foot-wide window, the net wall run is 38 feet. The gross wall area is 44 × 8, or 352 square feet. The door and window areas are subtracted to estimate net covered area.

Now assume the wallpaper roll is 20.5 inches wide and 33 feet long, and the pattern repeat is 20 inches. A wall height of 8 feet is 96 inches, which is already 4.8 repeats, so the drop must be cut to the next complete repeat: 100 inches, or 8 feet 4 inches. The roll length can provide three full drops at that length.

The 38-foot net wall run needs about 23 strips at 20.5 inches wide. At three strips per roll, that is 8 rolls before waste. Add a 10 percent allowance and round up to 9 rolls. Actual packaging, pattern match type, and layout around openings can change the order, so confirm with the product calculator or wallpaper supplier.

Measure the wall area carefully

Measure each wall from corner to corner at the height where wallpaper will end. For a full room, add the wall lengths to find the perimeter. If a room is not rectangular, split it into wall sections and add their lengths. Measure alcoves, chimney breasts, and returns separately because they add wall surface and may create extra corner cuts.

For a feature wall, enter only that wall's length as the total run and use one matching room. Do not subtract door or window openings if paper will continue across the area or if the opening is small enough that the offcuts cannot be reused. A large doorway or full-height opening can reduce the number of strips needed.

Measure the wall height in several places if the floor or ceiling is uneven. Use the greatest required drop length for a safe estimate, or calculate separate wall groups if heights differ substantially. Wallpaper is usually trimmed at the ceiling and baseboard, so add enough length to allow a clean cut and adjustment.

Pattern repeat and wallpaper matching

Pattern repeat is the vertical distance before the design repeats. A large repeat means each strip may need extra length so the motifs align at the seams. The label may also identify a straight match or a half-drop match. A half-drop pattern offsets each neighboring strip and can change how much paper is usable from one roll.

This calculator uses the repeat length to round the drop up to a whole repeat. That is a simplified straight-match estimate. It does not model half-drop, multi-drop, reverse-hang, random-match, or special design layouts. Check the roll label for the pattern match symbol and follow the manufacturer's cutting guidance.

For expensive, large-repeat, or mural wallpaper, have the supplier or installer calculate the roll count. Keep the roll labels and batch information. If additional paper is needed later, the same product may come from a different print batch and show a visible shade variation.

Roll width, roll length, and double rolls

Wallpaper products come in different roll widths and lengths. Some suppliers sell single rolls, double rolls, or packaged units with coverage stated in square feet or square metres. Use the actual dimensions or coverage for the unit you are buying. If the package is sold as a double roll, count the package as the roll unit when entering its full length.

A wider roll can cover more wall per drop, but its weight and handling may differ. A longer roll may yield more drops, unless the pattern repeat or wall height leaves a short remainder that cannot produce another full strip. The calculator uses the roll length and width you enter; it does not infer a brand's packaging convention.

Check whether the listed coverage is theoretical area or recommended coverage after matching. If the manufacturer publishes a project calculator, use it as a second check. Never compare two wallpaper products by roll price alone; compare their usable coverage, repeat, match type, and package size.

Doors, windows, and other openings

Doors and windows reduce wallpaper area, but they do not always reduce roll count by the full opening area. Wallpaper strips are cut in full vertical drops. A window may fall within the middle of a strip, leaving two pieces that must be fitted above and below it. Those pieces may not be long enough for another wall section.

Enter openings that have a meaningful effect on the wall run or area. If the room has several openings of different sizes, measure their total widths and areas carefully. The form uses one door size and one window size repeated in each room, so use separate calculations for rooms with different opening arrangements.

Do not subtract closets or alcoves that will also be wallpapered. Include returns into window reveals only if the wallpaper will cover them, and measure those surfaces separately if they are significant. An installer can advise which offcuts are likely to be reusable for a specific design.

Wallpaper waste and extra rolls

Waste allowance covers trimming at ceilings and skirting boards, pattern alignment, damaged sections, short offcuts, and small measurement differences. Simple rooms with plain wallpaper may have less waste than a room with many corners, windows, a large pattern repeat, or a half-drop match.

Choose the allowance based on the product and room rather than using one percentage for every job. Ask the retailer or installer for guidance when the wallpaper is expensive or hard to reorder. The calculator rounds the final quantity up to whole rolls after applying waste.

Avoid ordering an exact theoretical amount. Keep one unopened roll from the same batch if future repairs are likely and the supplier's return policy allows it. Confirm whether extra rolls can be returned before purchase, and store leftovers as the manufacturer recommends.

Estimate wallpaper cost

Enter the price per roll to estimate a basic wallpaper material total. The calculator multiplies the number of rolls after waste by that price. It does not add primer, lining paper, paste, tools, delivery, taxes, preparation, removal of old paper, or installation labor.

When comparing prices, check that each product has the same roll unit and comparable coverage. A double roll can cost more than a single roll but may provide more usable drops. A larger pattern repeat can also reduce the number of strips cut from each roll, so the least expensive roll may not be the lowest-cost choice for the room.

For a full project budget, list materials and labor separately. Wall repair, sanding, priming, and removal of old wallpaper can take significant time. Ask for an itemized estimate and confirm who is responsible for surface preparation.

Common wallpaper estimating mistakes

A common mistake is using floor area instead of wall perimeter and height. Wallpaper covers vertical walls, so a room's floor square footage does not tell you the wall coverage. Another mistake is forgetting to include all walls, returns, or the space above doors and windows.

People also overlook pattern repeat or confuse a single roll with a double roll. Both can make a roll appear to cover more wall than it really does. Check the label and enter the full dimensions for the package unit you are buying.

Finally, subtracting every opening can understate the number of usable strips. Offcuts around windows and doors may not fit elsewhere, especially with a large pattern. Use a waste allowance and confirm the cut plan before ordering a large project.

Limits of this wallpaper estimate

The calculator estimates rolls for rectangular rooms with repeated wall heights and a straight-match pattern repeat. It accounts for measured openings and waste, but it does not produce a strip-by-strip hanging plan. It also cannot determine whether a product has a half-drop match, reverse-hang requirement, mural layout, or special installation direction unless you account for that separately.

Sloped ceilings, stairwells, vaulted rooms, murals, alcoves, and irregular walls need separate measurements. Manufacturer coverage figures may use different roll or package definitions. Compare the estimate with the wallpaper label, supplier guidance, and an installer takeoff before buying.

Good wall preparation is part of a successful wallpaper job. Follow the product instructions for surface condition, primer, adhesive, soaking, and hanging. If the wall has moisture damage, loose paint, or an unknown coating, resolve that issue before covering it with wallpaper.