Wallpaper Calculator
About Wallpaper Calculator
Calculating Wallpaper Needs
Wallpaper calculation is trickier than paint because you must account for pattern repeat waste. A standard single roll covers approximately 28 square feet of wall after allowing for trimming and waste, while a double roll covers about 56 square feet. However, wallpapers with large pattern repeats can waste significant material on matching, reducing effective coverage by 15-25%. Getting the math right ensures you buy enough rolls from the same batch (important for color consistency) without excessive overbuying.
Pattern Repeat and Waste
Pattern repeat is the vertical distance between repeating elements of the design. A random match or no-repeat pattern wastes the least material. A straight match means the pattern aligns at the same height on adjacent strips. A half-drop match offsets by half the repeat height, creating more waste. The larger the repeat, the more material is lost to matching. A 24-inch repeat can waste up to one foot of wallpaper per strip.
How to Use This Calculator
Enter room perimeter (or length and width), wall height, number of doors and windows, roll width, roll length, and pattern repeat distance. The calculator determines the number of strips needed, usable strips per roll accounting for repeat waste, and total rolls to purchase. Results are rounded up since partial rolls are not sold.
Frequently Asked Questions
How do I measure pattern repeat?
Find one distinctive element in the pattern. Measure the distance until that exact element appears again vertically. This distance is the pattern repeat. It is usually listed on the wallpaper packaging or product specifications.
Should I buy extra rolls?
Yes, buy 1-2 extra rolls from the same batch. Wallpaper batches have slight color variations, and future repairs need matching material. Most stores accept returns of unopened rolls within a time period.
What is the difference between single and double rolls?
A single roll is typically 27 inches wide by 16.5 feet long. A double roll is the same width but twice the length (33 feet). Most wallpaper today is sold in double rolls though priced per single roll, which can be confusing.
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