Dividing wall area by roll area can leave you short of wallpaper. A roll must provide full height drops, and a repeating pattern can lengthen each cut.
The Whatson Wallpaper Calculator works with drops rather than area alone. It counts full drops across each wall, determines how many fit in a roll and rounds the roll count for each schedule row.
Take the roll label to the worksheet
Wall width and height follow the selected measurement unit. Roll width, roll length, pattern repeat and total trim allowance are metres.
The trim value is added once to each drop length. If you plan trimming at both ends, enter their combined allowance rather than the allowance for only one end.
The model rounds cut length to a whole pattern repeat when repeat is greater than zero. It does not simulate an offset or half drop matching sequence, so use the product’s matching instructions for a detailed cutting plan.
Why one wall gives four rolls
For a wall 12 ft wide and 10 ft high, use a roll 0.53 m wide and 10 m long, repeat 0.32 m and total trim 0.1 m.
The height plus trim is 3.148 m. Rounding to the pattern repeat gives a 3.20 m cut. Three full drops fit in a 10 m roll, while the wall needs seven drops across its width.
The checked base purchase is therefore three rolls. With a 5% spare allowance applied to whole rolls, the order rounds up to four rolls.
On a small order, even a modest percentage can add a whole extra roll. Inspect the base roll result before deciding the spare allowance you want.
Openings do not produce automatic savings
There is no door or window deduction in this calculator. Keeping full height drops avoids promising that pieces cut around an opening can be reused elsewhere.
The tool also does not pool leftover drops between different schedule rows. Combining several identical walls through quantity can behave differently from treating each wall as a separate row; group them only when that shared cutting assumption is appropriate.
Before buying all the rolls
Check the printed repeat and matching method, usable roll length and actual wall height. Confirm the batch details with the supplier if the whole room needs to match.
The rate is PKR per roll. Paste, wall preparation and installation are separate. Use the result as a conservative worksheet for the stated roll geometry, then confirm any more efficient cutting plan with the installer before reducing the order.