The pattern-repeat puzzle, explained.
Wallpaper is bought by the roll but installed in full-height strips, called drops. The mismatch explains why dividing wall area by roll area can leave you short.
Count drops across the wall
Divide the wall width by the roll width and round up. A 4 m wall with 0.53 m wide paper needs 8 drops. For several walls, calculate them separately when you want to reserve a full edge drop at each corner. Treating the total perimeter as one continuous wall can be less conservative.
Find a usable cut length
Add trimming allowance to the wall height. For a straight-match pattern, round that length up to a full number of repeats. A 2.4 m wall plus 0.1 m total trim needs 2.5 m. With a 0.64 m repeat, four repeats give a 2.56 m cut.
Convert cuts into rolls
A 10 m roll provides three 2.56 m drops. It cannot provide four: that would require 10.24 m. Eight drops therefore require three rolls. The remaining lengths may be useful for short areas, but do not assume they replace full drops before drawing a cutting plan.
Know when the simple method stops
Half-drop patterns alternate alignment. Our half-drop setting adds half a repeat to every cut as a conservative planning rule; a carefully arranged cutting sequence can differ. A/B products, murals and unusually large patterns require the manufacturer’s own instructions. Check the roll label and product-specific calculator before ordering.
Source: Graham & Brown measuring guide, consulted 9 November 2026, confirms measuring height and width and using the product calculator. Drop arithmetic and the conservative half-drop rule above describe this site’s model.