Wallpaper Calculator — How Many Rolls Do You Need?
Buying too few rolls is the classic wallpaper mistake — dye lots vary between batches, so you cannot easily top up later. This calculator works out the total wall area, subtracts your doors and windows, and rounds up to the nearest roll.
How we calculate
Wall area = 2 × (length + width) × height. Deduct 1.9 m² per door, 1.2 m² per window. Roll area = width × length. Rolls = ⌈(paperable area ÷ roll area) × (1 + waste %)⌉.
Worked example
Room 4 m × 3 m, 2.4 m walls, 1 door, 1 window, 0.53 m × 10 m rolls, 15% waste. Paperable area ≈ 30.5 m². Roll area = 5.3 m². Rolls = ⌈(30.5 ÷ 5.3) × 1.15⌉ = 7 rolls.
Common mistakes
- Buying exactly the minimum — always buy one extra roll in the same batch.
- Using a flat 10% for patterned wallpaper — large repeats waste 25–35% per drop.
- Measuring only two accent walls and forgetting the full perimeter.
Frequently asked questions
How many rolls of wallpaper do I need for a standard room?+
A typical 4 m × 3 m room with 2.4 m walls and one door and window requires around 6–8 rolls of standard 0.53 m × 10 m wallpaper with a 15% waste allowance. Rooms with large pattern repeats may need 10 or more rolls.
How much extra wallpaper do I need for a patterned design?+
Add 20–35% waste for patterns with a repeat larger than 30 cm, since you must align each drop before cutting. Plain or random-match wallpapers only need 10–15% extra. The pattern repeat length is printed on the roll label.
What is a standard wallpaper roll size?+
Standard European rolls are 0.53 m wide and 10 m long, giving 5.3 m² of coverage per roll. UK and US rolls may vary — always check the dimensions on the label before calculating.
Can I buy extra rolls later if I run short?+
It is risky. Wallpaper is printed in batches, and the colour can differ slightly between batches even within the same design. Always note the batch number when you buy, and purchase one or two extra rolls from the same batch for future repairs.