Wallpaper Calculator — Rolls, Pattern Repeat & Coverage
Calculate how many rolls of wallpaper you need for any room. Accounts for wall height, pattern repeat, doors, windows and the number of drops per roll — for both straight and offset match patterns.
How the wallpaper calculator works
- 1Usable length per roll: roll length (typically 10 m) minus waste per drop
- 2Drop length: wall height + pattern repeat (for matching)
- 3Drops per roll: usable length ÷ drop length, rounded down
- 4Total drops needed: room perimeter ÷ wallpaper width (typically 0.53 m)
- 5Subtract drops for door and window widths (each door ≈ 1.5 drops, each window ≈ 1 drop)
- 6Rolls needed: total drops ÷ drops per roll, rounded up; always add one extra roll
Worked example
Room: 4 × 3 m, walls 2.5 m high, two doors, one window. Plain wallpaper, 10 m × 530 mm rolls.
Perimeter: 14 m. Drops needed: 14 ÷ 0.53 = 26.4 → 27 drops − 4 for openings (2 doors × 1.5 + 1 window × 1) = 23 drops. Drops per roll: 10 ÷ 2.5 = 4. Rolls: 23 ÷ 4 = 5.75 → buy 7 rolls (including one spare).
Frequently asked questions
How many rolls of wallpaper do I need for a 12×12 room?
A 12×12 ft room (3.66 × 3.66 m) with 8 ft (2.44 m) ceilings needs about 7 rolls of standard 530 mm × 10 m paper, or 8 rolls including one spare. Pattern repeat or conservative waste can increase this to 9–10.
What is a pattern repeat in wallpaper?
The distance between one pattern motif and the next identical one. A 64 cm repeat means you lose up to 64 cm per drop to align the pattern. Large repeats (>50 cm) significantly increase the number of rolls needed.
How wide is standard wallpaper?
Most standard rolls are 530 mm (53 cm) wide and 10 m long — covering approximately 5 m² per roll before waste. Luxury and designer papers are often 700 mm or 900 mm wide on shorter rolls.
How much extra wallpaper should I buy?
Always buy at least one extra roll for mistakes, future repairs and batch matching. For large pattern repeats (>30 cm), buy two extra rolls. Dye lots change — you cannot buy matching paper later.
Should I line the walls before wallpapering?
Lining paper is recommended on new plaster (let it dry first) and when using a heavy or expensive paper. It provides a smooth base and improves adhesion. Hang lining paper horizontally to avoid seams coinciding.