Rolls needed for any room — with the pattern-repeat waste that catches everyone out, handled
properly.
How wallpaper math works
wall area = total wall width × height − openings × 10
usable per double roll = 56 sq ft × pattern factor
rolls = ceil( wall area ÷ usable )
The pattern factor accounts for match waste: ~0.9 for small repeats, ~0.83 for medium, ~0.72
for large. Paperhangers' rule: when in doubt, round up — a leftover roll is a repair kit; a
missing roll from a new lot is a visible seam.
Usable coverage per US double roll
| Pattern repeat | Usable coverage |
|---|
| None / random | ~56 sq ft |
| Up to 6″ | ~50 sq ft |
| 7–12″ | ~46 sq ft |
| 13–24″ | ~40 sq ft |
Frequently asked questions
How much does a double roll of wallpaper cover?
A standard US double roll (20.5″ × 33 ft) contains about 56 sq ft of paper, but pattern matching reduces usable coverage to roughly 44–50 sq ft for small repeats and as little as 36–40 sq ft for large repeats.
What is pattern repeat and why does it matter?
The vertical distance before the design repeats. Every strip must align with its neighbor, so you lose up to one repeat length per strip in trimming. A 24″ repeat can waste 15–25% of each roll — that is why this calculator asks for it.
Do I subtract doors and windows when calculating wallpaper?
Only large openings. The safe convention is to subtract half of each big opening — you still need full-height strips beside and above them, and partial strips rarely reuse well with a pattern.
Should I order all rolls at once?
Yes — always from the same batch/lot number. Different print runs have subtle color shifts that are invisible on the shelf and obvious on the wall. Order one spare roll for repairs.
Single roll vs double roll?
US wallpaper is priced per single roll but sold in double-roll bolts. If a website says "$45 per roll", the bolt on your doorstep costs $90 and contains ~56 sq ft. This calculator works in double rolls.