Running out of wallpaper one strip from the finish is worse than running out of almost anything — the replacement roll may be a different dye lot and visibly off. Enter your room below and buy right the first time.
How many wallpaper rolls do you need?
Enter your room size and roll type to get the number of wallpaper rolls to buy — pattern waste included.
Your estimate
Buy every roll from the same dye lot — the lot number is printed on the label, and shades vary between lots. Always buy one extra roll if the budget allows: it covers a bad strip now and a repair years later, when the pattern may be discontinued.
How to use this wallpaper calculator
- Measure the room's length, width and wall height.
- Count the doors and standard windows — we subtract them for you.
- Pick your roll type (check the label: most US wallpaper is sold as double rolls).
- Set the pattern repeat honestly — it is printed on the roll label and drives the waste.
How we calculate wallpaper
Wall area = 2 × (length + width) × height, minus 21 sq ft per door and 15 sq ft per window. Rolls = wall area increased by the pattern allowance (0% for random match, 10% small repeat, 20% large repeat), divided by the roll's coverage and rounded up — you cannot buy half a roll.
Wallpaper calculator FAQs
How many rolls of wallpaper do I need for a 12×12 room?
A 12×12 room with 8 ft ceilings has about 333 sq ft of wall after doors and windows — that is 6 US double rolls for a no-pattern paper, and 7 rolls once a pattern repeat is allowed for. The calculator above adjusts for both.
What is a double roll?
A double roll is simply twice the length of a single roll of the same paper. Most wallpaper is priced and sold as doubles even though it ships as one long roll — always compare and order in double rolls to avoid running short.
Why does the pattern repeat change the count?
Each strip must start at the right point in the pattern so the design lines up across the wall — the offcut between the ceiling line and the pattern match is waste. Bigger repeats waste more per strip, which is why large repeats add up to 20%.
Can I wallpaper over old wallpaper or glossy paint?
Over sound, well-bonded wallpaper, sometimes — but seams telegraph through and old adhesive can fail under new paste. Stripping first is the reliable route. Over glossy paint, scuff-sand and prime with wallpaper primer so the paste grips.