Wallpaper calculator: rolls to buy from wall width and height, roll size, pattern repeat and trimming, counted as full-height drops per roll.
更新于 已验证的示例：3
Each strip is 2.65 m long, so one 10.05 m roll gives 3 strips. Covering 14 m of wall takes 27 strips, which means 9 rolls.
Wall height plus trimming, rounded up to whole pattern repeats so every strip starts at the same point in the pattern.
Rounded down: an offcut shorter than a drop can't be hung.
Rounded up; doors and windows are not subtracted because their offcuts rarely fit elsewhere.
Rounded up to whole rolls; 0 spare drops left over.
Wallpaper is bought by the roll but hung in drops, the full-height strips cut from it. Each drop is the wall height plus a trimming allowance, rounded up to whole pattern repeats so the design lines up. Drops across the walls are the total width divided by the roll width, rounded up; each roll gives its length divided by the drop length, rounded down; rolls to buy are drops divided by drops per roll, rounded up.
The default is 14 m of wall, 2.5 m high, papered with 53 cm × 10.05 m rolls and a 53 cm repeat. Each drop is 2.65 m, a roll yields 3, and 27 drops need 9 rolls.
Offcuts shorter than a drop are waste, which is why dividing wall area by roll area undercounts. The default 35 m² of wall divided by 5.33 m² per roll suggests 7 rolls; hanging it takes 9.
核验来源：Python decimal: ⌈2.6/0.53⌉ × 0.53 = 2.65 m; ⌊10.05/2.65⌋ = 3; ⌈14/0.53⌉ = 27 drops; 27/3 = 9 rolls
核验来源：Python decimal in inches: ⌈100/21⌉ × 21 = 105; ⌊396/105⌋ = 3; ⌈480/20.5⌉ = 24; 24/3 = 8
核验来源：Hand calculation: 5.3/0.53 = 10 drops exactly; 10.05/2.5 = 4 drops per roll; 10/4 = 2.5 → 3 rolls
Count drops, not square metres. Divide the total wall width by the roll width and round up for the drops; divide the roll length by the drop length and round down for drops per roll; then divide and round up. A 14 m perimeter with 2.5 m walls, 53 cm × 10.05 m rolls and a 53 cm repeat needs 27 drops at 3 per roll, so 9 rolls.
In the UK a standard roll is 10.05 m long and 0.53 m wide, about 5.3 m², according to TradeCalculator UK, which also lists 0.70 m wide rolls and other designer sizes. Because sizes vary by maker, enter the width and length printed on your roll's label.
Each drop is rounded up to a whole number of repeats so every strip starts at the same point in the pattern. On a 2.4 m wall with 10 cm for trimming, plain paper needs 2.5 m drops and a 10.05 m roll gives 4 of them. A 53 cm repeat makes each drop 2.65 m and a roll gives only 3, so 27 drops take 9 rolls instead of 7.
Usually not. Full-height drops are still hung beside a door and short pieces above and below a window, and those offcuts rarely fit elsewhere, so TradeCalculator UK papers the whole perimeter by default. Deduct only wide full-height openings such as patio doors: a 1.8 m opening is about 3 drops of 53 cm paper.
Colour can differ between production runs, so rolls from two batches may not match when hung side by side. Buy every roll you need with the same batch number at once, and add at least one spare roll for repairs and mistakes, as TradeCalculator UK recommends.
准确性取决于输入值和方法的假设。十进制运算使用50位有效数字，但估算、数值方法和源数据的精度可能较低；显示时的舍入并不能消除这些限制。 已按独立来源核验的计算示例：3。 例如，“14 m of wall, 2.5 m high, 53 cm repeat”根据Python decimal: ⌈2.6/0.53⌉ × 0.53 = 2.65 m; ⌊10.05/2.65⌋ = 3; ⌈14/0.53⌉ = 27 drops; 27/3 = 9 rolls进行核验。
DecoratorsBest — wallpaper estimator with pattern repeat (drops-per-roll method); TradeCalculator UK — wallpaper rolls for 10.05 m × 0.53 m rolls.
此计算器包含 3 个已解示例，答案来自独立来源。这些示例会在测试套件中运行，你也可以在此运行验证。
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