🧻 Wallpaper Calculator
Enter your room dimensions, wall height, and roll size to find how many rolls of wallpaper to buy — with doors, windows, and pattern waste accounted for.
🧻 Room & Roll Details
What is a Wallpaper Calculator?
It turns a few measurements into the one number you need at the store: how many rolls of wallpaper to buy. From the room perimeter and wall height it computes the wall area, counts the drops each wall takes, cuts each drop to the wall height plus trim plus the pattern repeat, and works out how many whole drops a roll gives — rounding up so you never come up short mid-wall.
Use it to budget a feature wall or a whole room, avoid the frustration of a dye-lot mismatch on a second trip, and buy a sensible spare for future repairs. The figures are estimates for planning — confirm roll coverage on the label and measure carefully before you order.
❓ Frequently Asked Questions
How does the calculator work out how many rolls I need?
It counts drops, the full-height strips you actually hang. Each wall takes its width divided by the roll width, rounded up (a strip cannot turn a corner and carry on). Each drop is cut to the wall height plus about 4 inches of trim plus one pattern repeat, and a roll yields only the whole drops that fit in its length. The rolls to buy are the drops divided by drops per roll, rounded up. As a cross-check it also works the old way, wall area plus a waste allowance divided by roll coverage, and never orders fewer rolls than that. On a 12 x 10 ft room with 8 ft walls and standard 20.5 in x 33 ft rolls the area method says 7 rolls; the walls take 28 drops at 3 a roll, which is 10.
What roll size should I enter?
Check the roll label. A common standard is a roll about 20.5 inches wide and 33 feet long, which covers roughly 56 square feet, and those are the defaults here. European and specialty rolls differ, so enter the actual width and length printed on your rolls for an accurate count.
Why does it add a waste percentage?
Square feet hide the waste: the offcut at the end of every roll, the trim at the ceiling and floor, and the length lost lining up the pattern. Counting drops captures all three, so the waste percentage now only sets the area cross-check. Enter the pattern repeat from the roll label: a 21 inch repeat on 9 ft walls cuts a 33 ft roll into 2 drops instead of 3. Doors and windows barely help, since paper still runs above a door and above and below a window.
Should I buy extra for repairs?
Yes. Buy at least one spare roll and check that every roll shares the same batch (or run) number, since color can shift slightly between print runs. Keeping a matching offcut lets you patch damage later without a visible seam or color mismatch.