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Wallpaper Calculator

Enter the width of each wall, the wall height, the roll width and length and the pattern repeat. The calculator works out the number of strips, how many strips you get from each roll and the rolls to buy. Four walls totalling 14 m at 2.5 m high with 0.53 × 10.05 m rolls and no repeat need 9 rolls before waste.

Measurements

Units
Walls

Check the roll label; widths vary by brand and country.

Check the roll label.

From the label; 0 for no repeat (plain or random match).

Extra length for trimming at the top and bottom.

Results

Rolls

10

Strips
26
Strips per roll
3
Cut length per strip
8.33 ft

Doors and windows aren't subtracted; the leftover usually covers offcuts and matching.

Show the working
  1. Strips around the room⌈44 ft ÷ 20.5 in⌉ = 26
  2. Strip length8 ft + 4 in = 8.33 ft
  3. Rolls⌊33 ft ÷ 8.33 ft⌋ = 3; ⌈26 ÷ 3 × (1 + 10%)⌉ = 10

Material takeoff

ItemQuantityUnit priceCost
Wallpaper10 rolls–
Estimated total–

Enter your local prices to estimate the cost. Prices aren't stored anywhere.

Paper and orientation
Open the list

How to use the wallpaper calculator

  1. Choose Metric or Imperial.
  2. Add the width of each wall you will paper.
  3. Enter the wall height.
  4. Enter the roll width and roll length from the label.
  5. Enter the pattern repeat (0 for plain or random-match papers) and the trim allowance.
  6. Set a waste allowance.

How the calculation works

Strips = ⌈total width ÷ roll width⌉. Strip length = height + trim, rounded up to whole repeats when there is a pattern repeat. Strips per roll = ⌊roll length ÷ strip length⌋. Rolls = ⌈strips ÷ strips per roll × (1 + waste)⌉.

Worked examples

Bedroom, no repeat. Walls of 4, 3, 4 and 3 m (14 m), 2.5 m high, 0.53 × 10.05 m rolls, 100 mm trim: 27 strips of 2.6 m, 3 strips per roll, 9 rolls.

Same room, 64 cm repeat. Strip length 2.6 m rounds up to 5 repeats = 3.2 m. Still 3 strips per roll here, but with a larger repeat you can drop to 2 strips per roll and need half as many rolls again.

How to interpret the results

Round up and buy all rolls with the same batch number. Leftover rolls can often be returned unopened; check the shop’s policy.

Tips and common mistakes

  • Measure the height at several points; ceilings are rarely level.
  • Check the pattern match type (straight or drop match) on the label.
  • Start beside a window or in a corner that is least visible, and use a plumb line.
  • Remember feature walls are counted separately.

Straight match and drop match

With a straight match, the pattern lines up horizontally across every strip, so each strip starts at the same point in the repeat. With a drop match, alternate strips are offset by half a repeat, which can add waste when cutting. The calculator rounds each strip up to whole repeats, which covers straight matches; for drop matches, add a little to the waste allowance or to the trim length.

If your walls need boarding or skimming first, use the drywall calculator or the plaster calculator. Both can add their materials to the project materials list along with the wallpaper rolls, so the whole room is on one list.

Assumptions and limitations

The calculator assumes full-height strips on every wall. Very large openings, stairwells and sloping ceilings need a manual plan.

Frequently asked questions

How do I calculate wallpaper rolls?

Strips = total wall width ÷ roll width, rounded up. Strip length = wall height + trim allowance, rounded up to whole pattern repeats. Strips per roll = roll length ÷ strip length, rounded down. Rolls = strips ÷ strips per roll, rounded up.

How does the pattern repeat affect the number of rolls?

Each strip must start at the same point in the pattern, so its length is rounded up to a whole number of repeats. Large repeats waste more paper and reduce the strips you get per roll.

Should I subtract doors and windows?

Usually not. Offcuts around openings are rarely reusable because of pattern matching, so the calculator counts full walls.

What roll size should I enter?

The size on the roll label. Widths and lengths vary by brand and country.

How many spare rolls should I buy?

Buy rolls from the same batch number and keep one spare for repairs if you can.

Sources