Calculate exactly how many rolls of wallpaper you need for any room. Accounts for pattern repeat, doors, windows, and waste — so you don't end up one roll short halfway through the job.
Room dimensions
ft
ft
ft
Each ≈ 21 sq ft
Each ≈ 15 sq ft
Fireplaces, arches...
Wallpaper roll details
$
Mid-range: $25–$80/double roll
💡 Pattern repeat tip: Large pattern repeats significantly increase waste — an 18-inch repeat can waste 25–35% of each drop. Check your wallpaper's label for the repeat size.
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rolls needed
Including pattern repeat waste
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Paintable sq ft
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Wall drops
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Total cost
Gross wall area—
Openings deducted—
Net wall area to paper—
Usable length per roll drop—
Drops per roll—
Total drops needed—
Rolls (before rounding)—
Rolls to buy—
Frequently asked questions
How do I calculate how many rolls of wallpaper I need? ›
Calculate the total wall perimeter × ceiling height to get gross square footage. Subtract doors and windows. Divide the ceiling height by the usable drop length (which accounts for pattern repeat waste) to find how many drops per roll. Divide total wall width by roll width to find total drops needed. Divide by drops per roll to get number of rolls — then round up and add one extra for safety. This calculator does all of that automatically.
What is a pattern repeat and how does it affect how much wallpaper I need? ›
A pattern repeat is the vertical distance before the pattern repeats itself. To match patterns across adjacent strips, each strip must be cut to start at the same point in the pattern — meaning some wallpaper at the top or bottom of each strip is wasted. An 18-inch repeat on a 9 ft wall wastes up to one full 18-inch section per strip. Wallpapers with no repeat (solid colors, textures) have zero pattern waste.
What is the difference between a single and double roll? ›
US wallpaper is sold in single rolls (≈33 sq ft of coverage) and double rolls (≈56 sq ft of coverage — not exactly double due to width variations). Double rolls are the standard unit sold at most stores, though pricing is quoted "per roll" — be sure you know whether the listed price is for a single or double roll when comparing. European rolls are typically sold as single rolls of 10.05m length.
Should I buy extra wallpaper? ›
Always buy at least one extra roll beyond your calculated need — more if your wallpaper has a large pattern repeat. Wallpaper is manufactured in dye lots, and even the same pattern from a different lot can have a subtle color difference that shows on your wall. If you run short later and the dye lot has changed, it may be impossible to get an exact match. An extra roll is cheap insurance.
About this wallpaper calculator
This calculator uses the drop method — the most accurate approach for patterned wallpaper. It calculates the usable drop length from each roll after accounting for the pattern repeat, finds how many drops fit per roll, divides total drops needed by drops per roll, and rounds up to whole rolls. It supports US single and double rolls, European metric rolls, and custom sizes.
Matching dye lots
When buying wallpaper, always check that all rolls have the same dye lot number printed on the label. Rolls from different dye lots can have subtle color variations that become visible side by side on the wall. Buy all rolls at once — ideally from the same store inventory — to guarantee a matching lot.