Free wallpaper rolls calculator: strips, pattern repeat and openings done right, with bag-free roll counts and cost.
Your results will appear here.
Enter your values and press Calculate.
Enter the room length, width and wall height in imperial or metric units. Add the roll width and length from the wallpaper label (US single roll 20.5 in × 33 ft, Euro roll 53 cm × 10.05 m), plus the pattern repeat in inches or cm, or zero for plain paper. Enter the number of doors and windows, and the price per roll. The calculator uses the decorator-grade strips method: it divides the room perimeter into full-height strips, works out how many strips each roll yields after pattern repeat and trim, and rounds up to whole rolls, with a one-spare-roll recommendation and the total paper cost.
Decorators do not use simple area math, because it ignores the waste at the end of every roll. They use the strips (drops) method. First, strips needed = round up(room perimeter / roll width), minus one strip per door and per window. Second, cut length per strip = wall height + pattern repeat + trim allowance. Third, strips per roll = round down(roll length / cut length). Finally, rolls = round up(strips needed / strips per roll). For a 12x12 ft room with 8 ft walls, a US single roll (20.5 in × 33 ft), no repeat, one door and one window: 48 ft perimeter gives 29 strips minus 2 = 27 strips; each roll yields 4 strips of 8.25 ft; so 7 rolls, plus one spare.
Measure the room at floor level and enter length, width and wall height. Measure the height in several spots and use the largest, because floors are rarely level. Copy the roll width, roll length and pattern repeat straight from the wallpaper label, or choose the US or Euro standard presets. Count doors and windows, enter the price per roll, and the calculator returns the strips, the strips per roll, whole rolls needed, a spare-roll recommendation and the paper cost.
Measure the perimeter by measuring each wall separately and adding them, rather than doubling one room dimension; alcoves, chimney breasts and bay windows change the real total. Measure wall height at three points along each wall and keep the tallest. Note every door and window, including their sizes, since large openings earn their strip deduction. Write down the batch number of the rolls you buy, because a reorder from a different batch can visibly mismatch.
The US single roll is 20.5 inches wide by 33 feet long (about 56 sq ft of printed area), and US paper is usually sold as double rolls. The Euro and UK standard roll is 53 cm wide by 10.05 m long (about 5.3 sq m). Wide and commercial rolls run up to a metre wide, and peel-and-stick rolls are often wider but shorter. Printed coverage is not usable coverage: pattern repeat and trim eat several square feet from every roll.
The pattern repeat is the vertical distance before the design starts again, printed on the label. With a repeat, every strip must be cut longer so the pattern aligns with its neighbor, and that extra length is waste. Straight matches align simply; half-drop (drop) matches offset every other strip by half the repeat and waste more. Rough waste allowances: 5% for random or free match, 10 to 15% for small repeats, 15 to 25% for half-drop or large repeats, 20 to 30% for very large repeats. This calculator adds the repeat into the cut length automatically.
Subtract roughly one strip per door (a door is about 21 sq ft) and one per large window (about 15 sq ft). Do not subtract small windows: the offcuts around them are mostly unusable, and keeping them adds a safety margin. Never subtract inside the perimeter and then again as area; one deduction method at a time. When in doubt, keep the opening in the count, because running out mid-wall is far more expensive than one leftover strip.
Dividing wall area by roll coverage assumes every square inch of the roll lands on the wall, which never happens. End-of-roll waste, pattern repeat matching and trim allowance consume 10 to 25% of the paper, more with big patterns. Two rooms with identical wall area can need different roll counts if their pattern repeats differ. The strips method wins because it models what actually happens on the roll: whole strips, cut to length, with the offcuts honestly counted as waste.
Wallpaper is printed in batches, and colors drift slightly between them. Buy all your rolls from the same batch number (the dye lot), printed on the label, and buy one extra roll beyond the calculated count for repairs and mistakes. A future patch from a different batch can show a visible seam line. The calculator's rolls-with-spare figure is the number to take to the store.
The same math applies to peel-and-stick wallpaper: use the roll width and length on the label. For an accent wall, measure just that wall's width and height instead of the room perimeter; the strips logic is identical. Renters can wallpaper one wall with removable paper for the same effect at a fraction of the cost. Skip wallpapering behind very large furniture: it is wasted paper nobody will ever see.
One packet of paste typically covers about 5 rolls of standard paper, or one ready-mixed tub covers a small room. Paste-the-wall papers need paste on the wall, not the paper, which changes the quantity slightly. Paper prices range from budget vinyl at $20 a roll to designer papers at $200 or more. Professional installation usually costs $1 to $4 per square foot on top of the paper. Enter your per-roll price in the calculator to get the paper cost instantly.
With 8 ft walls, a standard US single roll (20.5 in × 33 ft), no pattern repeat, one door and one window, you need 7 rolls plus 1 spare, for 8 total. Enter your exact measurements in the calculator, since wall height and pattern repeat change the answer.
A US single roll is 20.5 inches wide by 33 feet long (about 56 sq ft), usually sold as double rolls. A Euro/UK roll is 53 cm by 10.05 m (about 5.3 sq m). Peel-and-stick rolls are often wider but shorter. Printed coverage is not usable coverage once repeat and trim are counted.
A double roll is simply two single rolls joined: twice the length, same width. US wallpaper is priced per single roll but often sold as doubles, so check the label carefully. Two singles and one double cover the same area.
The repeat is the vertical distance before the pattern starts again. Every strip must be cut longer to align the pattern, and the extra is waste: expect 10 to 25% more paper depending on repeat size and match type. Plain paper with zero repeat wastes the least.
Straight match repeats identically at the same height on every strip. Half-drop (drop) match offsets every other strip by half the repeat, creating a staggered pattern that wastes more paper. Half-drop designs can need 15 to 25% more rolls than straight-match ones.
Divide the roll length by the cut length (wall height + pattern repeat + trim), rounding down. A 33 ft roll on 8 ft walls with no repeat yields 4 strips; with a 12-inch repeat it yields 3. The calculator shows this number live for your inputs.
Subtract one strip per door and one per large window. Do not subtract small windows, since the offcuts around them are unusable and keeping them adds a safety margin. One deduction method at a time: never subtract both as strips and as area.
Buy one full spare roll beyond the calculated count, from the same batch number. Pattern repeat waste of 10 to 25% is already built into the strips math. The spare covers cutting mistakes and future repairs without a mismatched batch.
Colors drift slightly between print runs. Two batches of the same design can show a visible seam when hung side by side. Buy all rolls at once from the same batch, keep the label, and include the spare roll in that purchase.
A US single roll prints about 56 sq ft, but usable coverage is lower once pattern repeat and trim are removed: typically 40 to 50 sq ft for plain paper, less for large repeats. This is why the strips method beats simple area division.
One packet of paste covers roughly 5 standard rolls; one ready-mixed tub covers a small room. Paste-the-wall papers are pasted on the wall instead, which changes the quantity. Buy paste after you know your final roll count.
Paper for a 12x12 room at $30 a roll (8 rolls with spare) is $240. Add paste at about $15 and professional installation at $1 to $4 per square foot of wall area (around $384 for 384 sq ft at the low end). DIY saves the labor cost.
Work out exactly how many litres and cans you need for any paint job.
Find out exactly how many wallpaper rolls your walls need.
Gallons, liters, and primer for any paint job.
Tiles and boxes to buy for floors and walls.