Wallpaper Calculator
Estimate rolls of wallpaper for a room, with waste for matching.
Find how many rolls of wallpaper you need. Extra waste is added because pattern repeats mean parts of each roll are trimmed off.
How the Math Works
The Wallpaper Calculator uses a simple yet precise formula to determine how many rolls you'll need: rolls = wall area × (1 + waste) ÷ coverage per roll. First, it calculates the total wall area by multiplying perimeter by height. Then it adds a waste factor (typically 10-15%) to account for pattern matching, cutting errors, and future repairs. Finally, it divides by the roll's coverage area to give you the exact number of rolls required, ensuring you don't over or under-order.
Practical Applications
To use this calculator, start by measuring your room's perimeter and wall height. Enter these dimensions along with your wallpaper's coverage per roll (usually found on the packaging) and your expected waste percentage. The calculator instantly processes these values using the formula to output the precise number of rolls needed, saving you time in both measurement and purchasing decisions.
Day-to-Day Use
This calculator prevents the frustration of running out of wallpaper mid-project or ordering excessive amounts that waste money. By accounting for pattern matching waste upfront, it ensures you buy exactly the right amount, whether you're tackling a weekend DIY makeover or planning a professional renovation. This translates to cost savings, reduced trips to the store, and confidence that your project will go smoothly from start to finish.
Worked example
400 ft² of wall, 28 ft²/roll, 15% waste → 400 × 1.15 ÷ 28 = 17 rolls.
FAQ
Why so much waste?
Pattern repeats must align between strips, so the top of each strip is often cut off and discarded.