Wallpaper Quantity Estimator
Estimate wallpaper rolls from wall width and height, roll size and pattern repeat, using the drop (strip) method.
Your inputs
Results
Rolls needed
9
- Drops (strips) needed
- 25
- Drops per roll
- 3
- Cut length per drop (incl. 10 cm trim)
- 2.6 m
≈Estimate based on the stated model and assumptions
Notes for this result
- Buy all rolls from the same batch (lot) number so the colour matches, and consider one spare.
What this calculator does
Wallpaper is hung in vertical drops; pattern repeat means each drop must start at a matching point, which wastes paper.
Formula and method
Drop length = height rounded up to whole repeats + 10 cm trim; Drops per roll = floor(roll length ÷ drop)
Drops needed = ceiling(paperable width ÷ roll width); Rolls = ceiling(drops ÷ drops per roll)
Worked example
Calculated by this tool with its default inputs:
Inputs
- Total wall width to paper: 14 m
- Wall height: 2.5 m
- Roll width: 0.53 m
- Roll length: 10.05 m
- Pattern repeat: 0 cm
- Total width of doors/windows that need no full drops: 1 m
Results
- Rolls needed: 9
- Drops (strips) needed: 25
- Drops per roll: 3
- Cut length per drop (incl. 10 cm trim): 2.6 m
How to read the results
Large repeats can noticeably increase the number of rolls.
Assumptions and limitations
- Buy rolls from the same batch number.
Questions
Why not divide wall area by roll area?
Because offcuts from each roll often cannot be used for full drops.
Methodology and verification
- Result type
- Estimate based on the stated model and assumptions
- Formula version
- 1.0
- Automated verification
- 3 reference and validation test cases, checked against independently computed values. The site cannot be built if any of them fail.
- Editorial review
- Awaiting human editorial review. The explanation was drafted with AI assistance; the formula and examples are verified by the automated tests above.
Privacy
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