Last updated: 2026-06-16

Estimating Wallpaper Rolls

The number of rolls a room needs follows a short chain: total wall area, multiplied by a waste allowance, divided by the area a single roll covers. A roll covers its length times its width, so a standard $10 \text{ m} \times 53 \text{ cm}$ European roll spans $5.3 \text{ m}^2$. Because rolls are sold whole, the result is always rounded up.

Here $A$ is wall area, $L$ and $w$ are roll length and width, $f$ is the waste fraction, $a$ is the coverage per roll, and $N$ is the number of rolls.

Pattern Repeat and Matching

The waste allowance accounts for the offcuts lost when adjacent strips must line up. A plain paper or a random (free) match has almost no loss, so a 10% allowance suffices. A patterned paper has a vertical repeat — often 30 to 64 cm — and every strip must begin at the same point in the design, which discards part of each drop. A larger repeat means more waste, so 15 to 20% is typical. A straight match places the repeat at the same height on every strip; an offset (drop) match staggers it between strips and tends to waste a little more.

Buying from One Batch

Wallpaper is printed in production runs, and the shade can drift slightly between runs. Each roll carries a batch or lot number on the label. Buying every roll from the same batch keeps the colour consistent across the wall, and keeping one spare roll allows later repairs to match.

Worked Example

Consider a room with 35 m² of wall and a 15% waste allowance, papered with rolls 10 m long and 53 cm wide. Each roll covers 5.3 m², so the area including waste and the rolls required are: