Wallpaper Calculator

Enter your room dimensions and wallpaper specifications to find out exactly how many rolls of wallpaper you need. Input your room length, width, ceiling height, roll width, roll length, and pattern repeat — the calculator accounts for doors, windows, and wastage to give you a reliable roll count.

ft
ft
ft

Standard door: ~21 sq ft (3 ft × 7 ft)

Standard window: ~15 sq ft (3 ft × 5 ft)

in

Standard US roll width is ~20.5 inches

yd

Standard US double roll is ~16.5 yards

in

Enter 0 for no pattern repeat

Results

Rolls Needed

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Total Wall Area

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Net Area to Cover

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Coverage Per Roll

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Exact Rolls (before rounding)

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Wall Area Breakdown

Frequently Asked Questions

How much wallpaper do I need for a room?

To estimate wallpaper rolls, calculate the total perimeter of your walls multiplied by the ceiling height to get the total wall area. Subtract openings like doors and windows, then divide by the coverage area of one roll. Always add at least 10% extra for trimming and pattern matching.

Should I subtract doors and windows from my wallpaper calculation?

It depends on the source — some manufacturers recommend not deducting openings to avoid shortages, while others include them for a more precise estimate. Our calculator deducts standard door (21 sq ft) and window (15 sq ft) areas but adds a 10% wastage buffer to compensate. For safety, many professionals recommend ordering an extra roll anyway.

What is a wallpaper pattern repeat and why does it matter?

A pattern repeat is the vertical distance before the wallpaper design repeats itself. When hanging patterned wallpaper, each strip must be cut longer to align the design across strips, which wastes material. A larger pattern repeat means more waste per strip, requiring more rolls overall.

How do I adjust the number of rolls for a pattern repeat?

When you enter a pattern repeat, the calculator increases the usable strip length to the next multiple of the repeat height. This means each strip requires more material to keep the pattern aligned. The total rolls needed is then recalculated based on these longer strips.

How accurate is the wallpaper calculator result?

The result is a reliable estimate for standard rectangular rooms. For complex room shapes, very large pattern repeats, or rooms with many architectural features, the actual amount needed may vary. We recommend consulting a professional decorator and ordering a spare roll, as wallpaper dye lots can change between production runs.

What is a standard wallpaper roll size?

A standard US double roll is typically about 20.5 inches wide and 16.5 yards (49.5 feet) long, covering roughly 56 square feet. European rolls are often sold as single rolls at 20.5 inches wide by 11 yards. Always check the label of the specific wallpaper you plan to buy.

Why should I include a 10% wastage allowance?

Wastage accounts for trimming at ceilings and baseboards, pattern matching between strips, off-cuts that cannot be reused, and any mistakes during installation. A 10% buffer is standard for simple rooms; for complex layouts or large pattern repeats, a 15–20% buffer is safer.

What if my room is not rectangular?

For non-rectangular rooms, measure each wall individually and add the widths together to get the total perimeter. You can also calculate the total wall area manually and use the coverage-per-roll figure from the calculator to determine how many rolls you need.

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