Wallpaper Calculator
Enter the perimeter of your walls, the height, your roll dimensions and the pattern repeat from the label. The calculator works out strips needed, strips per roll with the repeat applied, and whole rolls to buy — with the trim allowance built in.
Shop calculators quietly assume plain paper. This one prices the pattern repeat honestly: with a repeat, every strip cuts to a multiple of the repeat, offcuts stop being reusable, and the roll count jumps — better to know before the till than after.
How to use
- Add up the wall lengths you are papering (perimeter) and subtract only large openings like doors if you prefer to work net.
- Read roll width and length from the label (standard metric rolls are 0.53 m × 10.05 m) and enter them exactly.
- Find the pattern repeat on the insert — the distance before the design repeats. Enter 0 for plain paper; the calculator rounds each cut up to the repeat automatically.
Frequently asked questions
How much extra wallpaper should I allow?
The built-in 10 cm per strip covers uneven ceilings and skirtings. Beyond that, order one spare roll for bold patterns or long rooms: repairs must come from the same batch number later, and discontinued lines are never reprinted.
Why does pattern repeat change the number of rolls?
Each strip must start at the same point of the pattern so the design lines up across the wall. That forces every cut to a multiple of the repeat, wasting a fixed offcut per strip — on a large repeat over a short wall, a 10 m roll can drop from four usable strips to three.
How do I measure the perimeter?
Wall length plus wall width, doubled, then subtract nothing for windows and doors — the offcuts and the spare-roll margin cover openings, and working gross is safer than running short mid-wall.
Do I paper behind wardrobes and radiators?
Behind a fitted wardrobe you can skip; behind radiators, paper — strips shrunk visibly at a radiator are the classic amateur tell. The pattern match across the radiator matters more than the saving.