Wallpaper Calculator
See exactly how many rolls to buy for your wall — coverage and waste allowance included.
Always rounds up
You can only buy whole rolls, so the result is rounded up to the next whole roll — never short halfway up the wall.
Add a waste allowance
Trimming and pattern matching eat into each roll — 15% extra is the usual rule of thumb for a patterned paper.
How many rolls of wallpaper do I need?
Wall area, roll size, and a little extra
The number of rolls you need comes down to three things: the wall area you are covering, the coverage of a single roll, and how much spare you keep for trimming and pattern matching. Multiply the wall area by your waste factor, divide by the coverage of one roll, and round up to whole rolls, and you have the number to buy. Enter your figures above to see both the roll count and the coverage of a single roll.
Enter your wall area, roll dimensions, and waste allowance to get the number of rolls to buy.
First work out the area one roll covers — its length times its width. Multiply the wall area by one plus the waste percentage, divide by that coverage, and round up.
Rolls = ⌈wall area × (1 + waste%) ÷ (roll length × width)⌉A standard 10 m × 0.53 m roll covers 5.3 m². Thirty square metres at 15% waste is 34.5 m²; divided by 5.3 that is about 6.51 rolls, rounded up to 7 rolls.
Suppose you are papering a 30 m² wall with standard 10 m × 0.53 m rolls and a 15% waste allowance.
Find one roll's coverage
10 m × 0.53 m = 5.3 m² per roll.
Add the waste allowance
30 × 1.15 = 34.5 m² of paper to cover.
Divide and round up
34.5 ÷ 5.3 = 6.51, rounded up to 7 rolls to buy.
The figure is the number of whole rolls to buy, so always round up — a part roll still means purchasing a full one. A 15% waste allowance suits most patterned papers; add 10–15% on top when the pattern has a large repeat, since each drop has to line up with the next and the offcut is trimmed away. Buy every roll in one purchase with the same batch number — colours drift between print runs — and keep a spare from that batch for future repairs.
The arithmetic is exact, but a real wall adds a few wrinkles.
Pattern repeats and openings
Papers with a large pattern repeat waste more than the figure suggests, because each drop must be aligned to the last before the top is trimmed — lean towards the higher end of the waste range for these. The calculator also works from the full wall area and only partially allows for doors and windows: the offcuts around openings are often unusable, so measuring the whole wall and adding waste is safer than subtracting every opening.