Calcylator
Wallpaper Rolls

Wallpaper rolls needed:
wall area ÷ roll coverage, plus waste

Measure the walls, subtract doors and windows, allow for pattern matching, and round up to whole rolls so you order enough in one batch.

Calcylator Editorial Team

Updated · 6 min read

How many wallpaper rolls do you need?

Divide the wall area plus a waste allowance by the coverage of one roll, then round up. A room with 33 m² of wall, rolls covering 5.3 m² each and 10% waste needs 33 × 1.10 ÷ 5.3 = 6.85, so 7 rolls.

The wallpaper rolls calculator takes three inputs: the wall area in square metres, the coverage per roll in square metres, and the waste percentage (0 to 30, default 10). It returns whole rolls, because a partial roll cannot be bought.

Wallpaper rolls formula and worked example

Wallpaper rolls required =rolls = ceil(wall area × (1 + waste ÷ 100) ÷ coverage per roll)
wall area:
area of walls to paper, in m²
coverage per roll:
area one roll covers, in m²
waste:
allowance for trimming and pattern matching, in percent
ceil:
round up to a whole roll

  • Room perimeter

    14 m

  • Wall height

    2.6 m

  • Gross wall area

    14 × 2.6 = 36.4 m²

  • Door and window

    3.4 m²

  • Net wall area

    33 m²

  • Coverage per roll

    5.3 m²

  • Waste

    10%

Rolls required

7

33 × 1.10 = 36.3 m², divided by 5.3 = 6.85, rounded up to 7.

  1. Add up the lengths of all the walls to get the perimeter.
  2. Multiply by the wall height to get the gross wall area.
  3. Subtract the area of doors, windows and large fixed openings.
  4. Check the coverage printed on the roll label, then apply the formula.

Pattern matching and the waste allowance

A plain paper wastes little, but a patterned one must line up across drops. Each strip is cut longer so the pattern can be matched, and the offcut is often unusable. Raise the waste allowance for a bold repeat.

Same 33 m² of wall, 5.3 m² per roll
WasteArea to cover (m²)Rolls required
10%36.37
15%37.958

A single feature wall shows the same arithmetic on a small scale. A wall 4 m wide and 2.6 m high is 10.4 m². With 15% waste that becomes 11.96 m², and 11.96 ÷ 5.3 = 2.26, so you need 3 rolls even though you are covering only a little over two rolls of surface.

Going from 10 to 15 percent adds a whole roll here, which is exactly why the order matters. Running short is the costly mistake, since a later batch can differ slightly in shade.

Practical ordering tips

  • Check the batch number on every roll and buy all rolls from the same batch.
  • Read the label for the roll width and length, and multiply them to get the coverage per roll if it is not stated.
  • Order one spare roll for repairs when the paper is a limited run.
  • Measure each room separately, then total the rolls for the project.

Rolls vary between countries and brands. Many UK papers are around 10 m long and 53 cm wide, but wide or mural papers differ, so always use the coverage stated on the actual product.

Common mistakes when counting rolls

  • Using the floor area instead of the wall area. Walls are perimeter times height.
  • Not subtracting windows and doors, which overestimates, or subtracting them with no waste allowance, which underestimates.
  • Mixing the coverage of a roll with the width. The coverage must be an area in square metres.
  • Forgetting that a high ceiling or a stairwell needs longer drops and more waste.

Common questions

How many rolls of wallpaper do I need for a room?

Divide the wall area plus waste by the coverage per roll and round up. For 33 m² of walls, 5.3 m² rolls and 10% waste, that is 33 × 1.10 ÷ 5.3 = 6.85, so you need 7 rolls.

How do I measure walls for wallpaper?

Add up the lengths of the walls to get the perimeter, multiply by the height, then subtract doors and windows. A 14 m perimeter and 2.6 m height give 36.4 m², and 3.4 m² of openings leaves 33 m².

How much extra wallpaper should I buy?

Ten percent is a common starting allowance and the calculator's default. Patterns that must be matched across strips may need 15 percent or more. Buy one batch for the whole room to keep the shade consistent.

Should I subtract windows and doors from the wall area?

Yes, subtract the area of doors, windows and other large openings, which lowers the roll count. Keep the waste allowance, though, because strips above and below openings still need trimmed pieces and pattern matching.

Was this guide helpful?

Continue reading

View all blogs