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 many rolls of wallpaper do I need?
Work in drops, not area. Divide the room perimeter by the paper width — usually 0.53 m or 21 in — to get the number of drops, subtracting roughly 1.5 drops per door and 1 per window. Then divide the roll length, typically 10 m or 33 ft, by your drop length to see how many drops a roll yields. Buy one spare roll from the same batch.
How does a pattern repeat change the count?
It adds waste to every single drop, because each one has to start at the same point in the pattern. Add the repeat to your drop length before dividing it into the roll: an 8 ft (2.4 m) wall with no repeat gives four drops from a 33 ft (10 m) roll, but a 20 in (500 mm) repeat pushes each drop past 9 ft and you get three. That is a 25% jump in rolls from one number on the label.
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How the wallpaper calculator works
- 1Usable length per roll: roll length (typically 10 m, or 33 ft) 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, or 21 in — US rolls are usually 27 in)
- 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 (13 × 10 ft), walls 2.5 m (8 ft) high, two doors, one window. Plain wallpaper, 10 m × 530 mm rolls — 33 ft × 21 in.
Perimeter: 14 m (46 ft). 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 (25 in) repeat means you lose up to 64 cm per drop to align the pattern. Large repeats — over 50 cm, or 20 in — significantly increase the number of rolls needed.
How wide is standard wallpaper?
Most European rolls are 530 mm (53 cm, or 21 in) wide and 10 m (33 ft) long — covering approximately 5 m², about 54 sq ft, per roll before waste. A US double roll is typically 27 in wide and covers 56–61 sq ft. 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 — over 30 cm, or 12 in — 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.