Wallpaper Calculator

How many rolls of wallpaper to buy, counted strip by strip from wall width, height, roll size, trim allowance and pattern repeat.

Add up the widths of every wall to cover (a 12 × 12 ft room is 48 ft).
US rolls are usually 20.5 in (52 cm) wide; European rolls 53 cm.
A US “double roll” is about 33 ft; a European roll is 10.05 m. Check the label.
Extra length per strip for trimming at the ceiling and baseboard; 2 in at each end is common.
$per roll
Your rate is remembered on this device.
Rolls to buy
10 rolls
Strips (drops) needed
29 strips
Full strips per roll
3 strips
Cut length per strip
100.0
Wall area
384
Estimated wallpaper cost
$400.00
Excludes paste, liner paper and labor. Buy all rolls from the same batch (dye lot).

Estimate generated with SortedSums: https://sortedsums.com/wallpaper-calculator/. For informational purposes only; verify before relying on it.

How it’s calculated

Wallpaper is hung in vertical strips, and leftover pieces shorter than a full strip are usually waste. So we count whole strips rather than dividing areas.

Cut length = wall height + trim, rounded up to whole pattern repeats (+ ½ repeat for a half-drop) Strips per roll = ⌊ roll length ÷ cut length ⌋ Strips needed = ⌈ total wall width ÷ roll width ⌉ Rolls = ⌈ strips needed ÷ strips per roll ⌉

Example: 48 ft of wall, 8 ft high, 20.5 in × 33 ft rolls, 4 in trim, no pattern. Cut length = 96 + 4 = 100 in; ⌊396 ÷ 100⌋ = 3 strips per roll. 576 ÷ 20.5 = 28.1 → 29 strips; 29 ÷ 3 = 9.67 → 10 rolls. With a 21 in straight-match repeat the cut becomes ⌈100 ÷ 21⌉ × 21 = 105 in, still 3 per roll and 10 rolls.

Doors and windows are not deducted: the offcuts above and below them rarely save a full strip. Order one extra roll for repairs.

Frequently asked questions

How many rolls of wallpaper for a 12 × 12 room?

With 8 ft walls and 20.5 in × 33 ft rolls, 48 ft of wall needs 29 strips at 3 per roll, so 10 rolls with no pattern repeat.

What is a double roll?

US wallpaper is priced by the single roll but sold in double rolls of about 56 ft² (20.5 in × 33 ft). Enter the length of the roll you actually receive.

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Sources

Formulas are taken from the free public references above. Results are provided “as is” for informational and educational purposes only. See our disclaimer.

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