Wallpaper Calculator

How to use this wallpaper calculator

1. Pick your units, metres or feet.
2. Enter the room length and room width (the floor measurements).
3. Enter the wall height from floor to ceiling.
4. Check the roll length and roll width, the defaults match a standard roll but your label may differ.
5. Set the waste percentage, then read the rolls needed, it updates as you type.

Nothing is submitted or stored: your measurements never leave your device.

How to estimate wallpaper rolls

The maths behind the tool is straightforward. First find the perimeter of the room, which is2 × (length + width). Multiply that perimeter by the wall height to get the totalwall area you need to cover. A single roll covers its own length × width, so dividing the wall area by the area of one roll tells you roughly how many rolls the paper would stretch across.

Paper is never used perfectly, so the calculator adds about 10 to 15 percent for pattern matching and waste, then rounds up to the next whole roll. The result is: rolls = wall area × (1 + waste) ÷ roll area, rounded up. We deliberately do not subtract doors and windows, that extra paper becomes your safety margin so you are far less likely to run short midway through a wall.

A quick worked example

Take a 4 m by 3 m room with 2.4 m walls. The perimeter is 2 × (4 + 3) = 14 m, and 14 × 2.4 = 33.6 m² of wall. A standard roll of 10 m × 0.53 m covers 5.3 m². With 15 percent added for waste, 33.6 × 1.15 = 38.6 m², divided by 5.3 gives 7.3, which rounds up to 8 rolls. Buy from the same batch number where you can, so the colour matches across every roll.

Note: This is an estimate to help you shop with confidence, not an exact cutting plan. Large pattern repeats, sloped ceilings, and feature walls can change the count, so always check the roll label and keep a spare roll.

Frequently asked questions