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Wallpaper Calculator - How Many Rolls Do I Need?

Miscellaneous

Calculate exactly how many wallpaper rolls you need for any room. Enter room dimensions, door and window counts, roll size, and pattern repeat.

Room Dimensions

Wallpaper Roll

This is a straight-match estimate. Each drop is rounded up to a whole pattern repeat after trim allowance; use 0 when no extra trimming length is needed.

10 %
7
rolls to buy
Perimeter44 ft
Total Wall Area352 sq ft
Opening Deduction51 sq ft
Net Wall Area301 sq ft
Cut Drop Length8 ft
Trim / Drop0 ft
Strips / Roll4
Strips Needed23

How to use this tool

  1. Enter the room length, width, and ceiling height.
  2. Enter the number of doors and windows.
  3. Enter the wallpaper roll width, length, pattern repeat (0 if none), and any trim allowance per drop.
  4. Set your desired waste percentage (10 % is typical).
  5. Read the number of rolls to buy from the results panel.

How the wallpaper estimate works

The calculator finds the room perimeter, multiplies it by wall height, and subtracts the standard opening deductions selected for doors and windows. It then divides the resulting wall area into vertical strips based on the roll width. The final roll count is rounded up after the waste percentage is applied, so it is a planning estimate rather than a substitute for a measured cut list.

Pattern repeat and cut-drop length

For straight-match wallpaper, adjacent strips must begin at the same point in the pattern. The calculator first adds the trim allowance to the wall height, then rounds that required length up to a whole pattern-repeat multiple. It does not simply add one full repeat to every drop: an 8-foot wall with a 24-inch repeat is already four complete repeats before trim. Enter the repeat from the roll label and the extra length needed to trim the top and bottom.

Trim allowance and usable strips

Trim allowance defaults to zero because the amount depends on your installation. If you need extra paper above and below the wall, enter that total for each drop. The calculator uses the resulting cut-drop length to determine how many complete strips fit in a roll. Taller walls, large repeats, and extra trim all reduce the number of strips available from each roll.

Straight-match assumption

This estimator models straight-match wallpaper only: each strip starts at the same point in the pattern. Half-drop, offset, random-match, murals, and irregular walls can use materially more paper. Confirm the manufacturer's match type and layout instructions, and increase the waste percentage or request a professional layout for those cases.

Buying tips

Buy all rolls from the same dye lot when possible, check the manufacturer's stated coverage, and round up if the estimate is close. Standard American double rolls are often 20.5 inches wide by 33 feet long, while many European rolls are 52 cm by 10 m, but the roll label is the source of truth for a purchase.

Frequently asked questions

How does the wallpaper calculator account for pattern repeats?

For straight-match wallpaper, the calculator adds your trim allowance to the wall height, then rounds that required drop up to a whole pattern-repeat multiple. For example, an 8 ft drop with a 24 in repeat is an 8 ft cut before any trim, not a fixed extra 24 in. Offset and half-drop patterns need a separate layout estimate.

Should I include doors and windows in my wall measurement?

Yes - measure the full perimeter and full height, then enter the number of doors and windows. The calculator deducts a standard 21 sq ft per door and 15 sq ft per window from the total.

What waste percentage should I use?

Most professional paperhangers recommend 10–15 % waste for plain wallpaper and 15–20 % for large pattern repeats. Complex rooms with many angles may need up to 20 %.

What are standard wallpaper roll sizes?

American double-rolls are typically 20.5 inches wide × 33 feet long (covering ~57 sq ft). European single rolls are commonly 20–21 inches wide × 33 feet long. Always check the roll label.

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