Wallpaper Calculator
Count wallpaper rolls strip by strip for a room, with pattern repeat, match type, paste and total cost. Free, no sign-up, and it runs in your browser.
Dedicated page: /en/wallpaper-calculator
Each door removes 3 ft of wall width.
Each window removes 3 ft of wall width.
Printed on the roll label. 0 for plain or random-match paper.
Extra top and bottom for trimming. 4 in total is typical.
Dye lots vary between print runs. Keep a spare for repairs.
Vinyl-coated paper runs $20 to $50 a single roll; designer paper $100 to $300+.
Professional hanging is typically $2 to $4 per sq ft. Leave 0 for DIY.
Rolls are counted strip by strip, not by dividing wall area by roll area: every strip must start at the right point in the pattern, so area-only maths under-orders on patterned paper. Always check the label coverage before ordering.
Quick answer
A wallpaper calculator works out how many rolls a room needs, counted strip by strip. Enter the room size, doors and windows, roll size, pattern repeat and match type, and it shows the strips needed, how many strips fit on one roll, the rolls to buy with a spare, the paste needed and the total cost.
About this Wallpaper Calculator
Count wallpaper rolls strip by strip for a room, with pattern repeat, match type, paste and total cost. It is one of the Home and DIY on ToolUstad, and like every tool here it runs entirely in your browser: nothing you type, paste or open is uploaded to a server, and there is no sign-up or usage limit.
What is a wallpaper calculator?
Wallpaper hangs in whole strips, so the only correct way to count rolls is to work out how many strips the room needs and how many strips fit on one roll, then divide. Dividing wall area by roll area under-orders on patterned paper, because it ignores the waste from aligning the pattern at the seams. On a 12 by 12 ft room with 8 ft ceilings, the area method says 6 rolls. The strip method says 8 rolls, plus a spare.
The maths runs in five steps. The perimeter is twice the length plus the width: 48 ft for a 12 by 12 room. Doors and windows remove 3 ft of wall width each, leaving a net width of 39 ft. Strips needed is the net width divided by the roll width, rounded up: 468 inches divided by 20.5 inches is 23 strips. Each strip is cut to the wall height plus a trim allowance, 8.33 ft with 4 inches of trim. Strips per roll is the roll length divided by the strip length, rounded down: 33 ft divided by 8.33 ft is 3 strips. 23 divided by 3 is 8 rolls, plus 1 spare, so buy 9.
Pattern repeat and match type
The pattern repeat is the vertical distance between two identical points in the pattern, printed on the roll label. It is the single input that changes the answer most. With no repeat, plain or random-match paper, the strip is cut to the wall height plus trim. With a straight match, the strip is cut to the next whole repeat above the wall height: a 21 inch repeat on an 8 ft wall makes each strip 8.75 ft, because 8.33 ft rounds up to 5 repeats of 21 inches. With a drop match, the pattern shifts half a repeat on alternate strips, so the cut rounds up to the nearest half repeat.
Roll sizes, cost and paste
Roll sizes are not standardised. A US single roll is 20.5 inches by 33 ft, about 56 sq ft. A commercial or wide roll is 27 inches by 27 ft, about 60 sq ft.
Cost splits into paper, paste and hanging. Budget vinyl-coated paper runs $20 to $50 a single roll, solid vinyl $30 to $80, non-woven paste-the-wall $40 to $120, peel-and-stick $30 to $60, grasscloth $80 to $200 and designer or hand-printed paper $100 to $300 or more. Paste runs about 1 tub per 4 rolls at $12 a tub.
Best practices
- Order one extra roll: dye lots vary between print runs, and patterns are discontinued regularly.
- Buy all rolls from one batch: check the lot number on every roll before you open them.
Common mistakes to avoid
- Dividing wall area by roll area and under-ordering on patterned paper by 2 or 3 rolls.
- Forgetting the trim allowance, which turns 4 strips per roll into 3 on an 8 ft wall.
- Ordering a top-up months later and finding the dye lot does not match.
Who is the wallpaper calculator for?
Homeowners papering a room, renters planning an accent wall with peel-and-stick, and decorators comparing roll sizes and pattern repeats before ordering.
Learn: how to use the Wallpaper Calculator
- Enter the room length, width and wall height in feet.
- Count the doors and windows. Each one removes 3 ft of wall width from the strip count.
- Pick a roll size, or enter a custom width and length. US single rolls are 20.5 in by 33 ft.
- Enter the pattern repeat from the roll label, and pick the match type: free, straight or drop.
- Read the strips needed, strips per roll, rolls to buy with the spare, paste tubs and total cost.
Features
- Strip-by-strip counting, the industry method, not area divided by roll area
- Pattern repeat with free, straight and drop match types
- Four roll presets: US single, US double, Euro and commercial wide
- Doors and windows subtracted by wall width
- Spare roll option, because dye lots vary between print runs
- Paste tubs at 1 per 4 rolls, installation cost, and a roll-size comparison table
Worked example
A 12 by 12 ft room with 8 ft ceilings, 1 door and 2 windows, using a US single roll 20.5 in by 33 ft with no pattern repeat: the perimeter is 48 ft and the net wall width is 39 ft after the openings, so 23 strips are needed. Each strip is cut to 8.33 ft with trim, so 3 strips fit on a roll and 8 rolls are needed, plus 1 spare, 9 rolls to buy. Wall area is 384 sq ft and net area is 333 sq ft. At $35 a roll plus 3 tubs of paste at $12, the total is $351.
Frequently asked questions
How many rolls of wallpaper for a 12x12 room?
About 8 standard US single rolls for a 12 by 12 ft room with 8 ft ceilings, 1 door and 2 windows, plus 1 spare roll, so buy 9.
What is pattern repeat and why does it matter?
The vertical distance between two identical points in the pattern. A 21 in repeat means you waste up to 21 in per strip aligning the seams.
What is the difference between single and double rolls?
A single roll is 20.5 in by 33 ft, about 56 sq ft. A double roll is 20.5 in by 66 ft, about 112 sq ft. Most wallpaper is sold in double rolls but priced per single roll.
What is the difference between straight match and drop match?
Straight match repeats at the same height on every strip, so each strip is cut to the next whole repeat above the wall height. Drop match shifts the pattern half a repeat on alternate strips, so the cut length rounds up to the nearest half repeat.
Should I deduct windows from the wallpaper area?
For the strip count, yes, by width: each door or window removes 3 ft of wall width. Some hangers do not deduct windows at all, because the short strips above and below still need paper.
How much does wallpaper cost?
Budget paper $20 to $50 per single roll, mid-range $50 to $100, designer or luxury $100 to $300 or more, peel-and-stick $30 to $60.
How much paste do I need?
About 1 tub of paste per 4 rolls for paste-the-wall paper, at roughly $12 a tub. Peel-and-stick paper needs no paste at all.
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