Wallpaper Calculator UK
Work out how many rolls you need from the wall run, wall height, the actual roll dimensions and the pattern match printed for your wallpaper.
Calculate wallpaper rolls
Enter the figures from the wallpaper label or product page. This calculator does not assume one universal roll size, trim allowance or pattern repeat.
How the wallpaper roll calculation works
Full-width drops = papered wall run ÷ actual roll width, rounded up.
The calculator uses wall height plus your own cutting allowance, then accounts for the selected free, straight or offset match before rounding up to whole rolls.
This drop-based method is more useful than dividing wall area by roll area because pattern matching can make part of a roll unusable even when the nominal square metres look sufficient.
Free, straight and offset matches are different
No pattern alignment is required between adjacent drops. Only the drop height and any cutting allowance consume length.
Adjacent drops must start at the same pattern position. The calculator uses the vertical repeat you enter to account for alignment offcuts.
Adjacent drops start at an offset position. Enter both the vertical repeat and the stated offset/drop rather than assuming it is always half the repeat.
Worked example
Use the actual wallpaper product data
Wallpaper dimensions and match details vary. Current UK manufacturer product pages show examples at 52 cm and 68.6 cm widths, 10.05 m lengths and half-drop patterns with different vertical repeats. That is why the calculator leaves the product dimensions editable rather than declaring one size “standard”.
Openings need judgement
A large door or window can reduce paper use, but a simple area deduction can also understate the number of full drops you must cut around it. For a complicated room, work wall by wall or use the Room Decorating Quantity Estimator to organise the measurements before returning here for the roll calculation.
Before ordering wallpaper
- Check the exact roll width and length on the product label or current product page.
- Use the stated pattern match, vertical repeat and offset/drop where applicable.
- Decide your own cutting allowance rather than relying on a hidden percentage.
- Round only at the final whole-roll step.
- If you want spare wallpaper from the same production batch, add reserve rolls explicitly instead of hiding them inside the calculation.
Frequently asked questions
How many rolls of wallpaper do I need?
It depends on the papered wall run, wall height, actual roll dimensions and pattern match. The calculator converts the wall run into full-width drops, works out how those drops fit into each real roll, then rounds up to whole rolls.
What is a wallpaper pattern repeat?
It is the vertical distance before the design repeats. For patterned paper, that repeat can create alignment offcuts between drops.
Does half-drop wallpaper use more paper?
It can. Offset or half-drop patterns require adjacent drops to start at different positions in the design. Use the repeat and offset stated for the exact wallpaper rather than applying a generic waste percentage.
Should I subtract doors and windows?
Not automatically by area. Wallpaper is normally purchased and cut as vertical drops, so openings can still require full drops around or above them. Measure the real wall layout and use judgement for major unpapered sections.
Sources checked for this calculator
- Graham & Brown — wallpaper FAQs and design-match definitions
- Harlequin / Sanderson Design Group — example product dimensions, repeat and half-drop match
Planning estimate only. Check the exact wallpaper label/product page and, for specialist or complex matches, the manufacturer’s own hanging guidance before ordering and cutting.