Wallpaper Calculator

Calculate the number of wallpaper rolls needed for a room with pattern repeat and door or window deductions.

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1. Enter the room perimeter and ceiling height, or provide individual wall dimensions for non-rectangular rooms. 2. Specify the wallpaper roll width and length based on the product you plan to purchase. 3. Enter the pattern repeat distance if your wallpaper has a repeating design that requires alignment. 4. Deduct standard or custom-sized doors and windows to reduce the calculated wall area. 5. Review the total rolls needed, usable strips per roll, and total strips required for the room.

About This Tool

Wallpapering a room requires precise calculations to avoid running short mid-project or spending money on unnecessary rolls. This wallpaper calculator determines exactly how many rolls you need based on your room dimensions, the wallpaper roll size, pattern repeat length, and deductions for doors and windows. Getting the number right is especially important because wallpaper from different print runs can have slight color variations.

The calculator accounts for pattern repeat - the vertical distance between identical points in the wallpaper design. Larger pattern repeats create more waste because each strip must be aligned with the previous one, requiring extra material that gets trimmed away. A wallpaper with a 24-inch repeat wastes significantly more than one with no pattern or a small repeat, and this calculator factors that in automatically.

Enter your room perimeter and ceiling height (or individual wall dimensions for non-rectangular rooms), along with the roll width and length. The tool deducts standard door and window areas, applies the pattern repeat waste factor, and tells you the total number of rolls to purchase. It also shows usable strips per roll and total strips needed, so you can verify the math yourself.

Formula / How It Works

Strips Needed = Room Perimeter / Roll Width | Usable Strip Length = Roll Length - (Roll Length mod Pattern Repeat waste) | Rolls = Strips Needed / Strips per Roll

Frequently Asked Questions

Pattern repeat is the distance between identical points in the wallpaper design. Each strip must be cut so the pattern aligns with the adjacent strip, which means extra material is trimmed as waste. A larger pattern repeat means more waste per strip. For example, a 24-inch repeat on a standard 33-foot roll might reduce usable strips from 4 to 3 per roll, increasing the total rolls needed by 25% or more.
In the United States, a standard single roll is 27 inches wide and about 27 square feet in coverage (approximately 4.5 yards long). A double roll - which is what is typically sold - is about 27 inches by 9 yards, covering roughly 54 square feet. European rolls are commonly 53 cm (21 inches) wide and 10 meters (33 feet) long, covering about 56 square feet.
A standard door opening is approximately 21 square feet and a standard window is approximately 15 square feet. Subtract these from your total wall area. However, you still need full-width strips above and below windows and above doors, so the actual savings is less than the full opening area. This calculator handles these partial strips correctly.
Order at least one extra roll beyond the calculated amount. This covers unexpected mistakes, miscuts, and future repairs. Because wallpaper batches can vary in color, having spare rolls from the same print run is important for seamless repairs later. For rooms with many windows or complex layouts, consider ordering two extra rolls.
A straight match means the pattern aligns at the same height on adjacent strips - simply line up the edges and the pattern continues. A drop match (or offset match) means the pattern on the next strip must be shifted down by half the repeat distance to align. Drop match patterns typically produce more waste because every other strip starts at a different point.

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