Wallpaper Quantity
Free Wallpaper Quantity calculator with clear step-by-step results.
About Wallpaper Quantity
Wallpaper is counted in drops, not in square metres. Divide the perimeter by the roll width to get the number of vertical drops, then work out how many whole drops a roll yields once the cut length includes trim and pattern matching. Because only whole drops are usable, a 10 m roll giving two 2.7 m drops wastes far more than the arithmetic suggests — which is exactly why the drop-based method is the trade standard.
Formulas
Drops and cut length
Drops = ceil(perimeter ÷ roll width); cut length = wall height + pattern repeat
Rolls
Rolls = ceil(drops ÷ floor(roll length ÷ cut length))
Worked example
With the default values below, Wallpaper Quantity returns Rolls to Buy of 11. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Room perimeterminimum 0 m
- 16 m
- Wall heightminimum 0.5 m
- 2.4 m
- Roll lengthminimum 1 m
- 10 m
- Roll widthminimum 0.1 m
- 0.53 m
- Pattern repeataccepts 0–120 cm
- 32 cm
Results
- Rolls to Buy
- 11 rolls
- Drops Needed
- 31 drops
- Usable Drops per Roll
- 3 drops
- Cut Length per Drop
- 2.72 m
Step by step
- 1Values used
- 2Drops and cut length
- 3Rolls
- 4Rolls to Buy= 11 rolls
- 5Drops Needed= 31 drops
- 6Usable Drops per Roll= 3 drops
- 7Cut Length per Drop= 2.72 m
Assumptions and limits
- The result is derived only from the 5 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
- Roll dimensions, repeat and recommended overlap vary by product. Check the label and buy all rolls from one batch before starting.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Roll dimensions, repeat and recommended overlap vary by product. Check the label and buy all rolls from one batch before starting.
Frequently Asked Questions
Why does the pattern repeat waste paper?
Each drop has to start at the same point in the design, so up to one full repeat is trimmed off every length. A 64 cm repeat on a 2.4 m wall can cut a roll from four usable drops down to three.
Should I deduct doors and windows?
Only large openings such as patio doors or a full wall of glazing. Standard doors and windows are normally left in, because the paper around them still needs pattern-matched drops and the offcuts rarely reach far.
How many spare rolls should I get?
One, from the same batch. Batch numbers differ in shade, and a single damaged drop later is much cheaper to fix from a matching spare roll than by repapering the wall.