Wallpaper Calculator
Estimate wallpaper rolls, cost, and waste for any room. Supports multiple walls, doors & windows, pattern repeat, and US/metric units.
Wallpaper calculator
Sum of all wall lengths you will cover.
Wallpaper roll details
Typical: 20.5 in (0.52 m) or 27 in (0.685 m).
Typical single roll: 33 ft (10 m).
Enter 0 if there is no pattern match.
Covers pattern matching & mistakes.
To estimate total material cost.
For some brands that sell double rolls.
How this wallpaper calculator works
This tool is designed to be more practical than the simple “area ÷ coverage” calculators you’ll find on many wallpaper stores. It lets you:
- Work in either feet/inches or meters/centimeters.
- Use a quick simple room mode or a detailed multi-wall mode.
- Optionally subtract doors and windows.
- Account for pattern repeat and waste.
- Estimate total material cost from your price per roll.
1. Calculate wall area
For each wall, the basic area is:
Wall area = wall height × wall width
In simple mode, you enter the room perimeter and wall height, so the calculator uses:
Total wall area = perimeter × wall height
In advanced mode, it sums the area of each wall you add.
2. Subtract doors and windows (optional)
If you choose to subtract openings, the net area is:
Net area = total wall area − door area − window area
In simple mode, the calculator uses standard sizes for doors and windows. In advanced mode, you can enter the exact total area.
3. Coverage per roll
Ignoring pattern repeat, the theoretical coverage of one roll is:
Roll coverage = roll width × roll length
However, pattern matching and trimming reduce the usable length. If you enter a pattern repeat, the calculator:
- Computes the effective drop length as wall height rounded up to the next multiple of the pattern repeat.
- Divides the roll length by this effective drop length to find how many full drops (strips) you can cut.
- Multiplies the number of drops by the roll width to get the usable coverage.
4. Waste / safety margin
To cover pattern alignment, trimming at floor/ceiling, and small mistakes, you should add a safety margin:
Adjusted area = net area × (1 + waste%)
The slider lets you choose 0–25%. Most decorators use 10–15%.
5. Number of rolls and cost
Finally, the calculator divides the adjusted area by the usable coverage per roll:
Rolls needed = adjusted area ÷ coverage per roll
Final rolls to buy = ceiling(rolls needed)
If you enter a price per roll, the estimated material cost is:
Total cost = final rolls × price per roll
Practical tips for ordering wallpaper
Measure carefully
- Measure each wall in at least two places and use the largest height and width.
- Note any sloped ceilings or irregular shapes and treat them as rectangles that fully cover the area.
When to add an extra roll
- Large or complex pattern repeats (e.g., 25 in / 64 cm or more).
- Rooms with many windows, doors, or niches.
- If the wallpaper may be discontinued or has a specific dye lot.
Standard wallpaper roll sizes
Common roll sizes (check your product label):
- US single roll: 20.5 in × 33 ft (about 56 ft²).
- US double roll: 20.5 in × 66 ft (about 112 ft²).
- European roll: 0.53 m × 10.05 m (about 5.3 m²).
FAQ
How do I calculate how many rolls of wallpaper I need?
Measure the height and width of each wall, subtract large doors and windows if desired, then divide the total area by the usable coverage per roll. Our calculator does this automatically and adds your chosen waste margin.
Should I subtract doors and windows?
For small openings, many installers ignore them and keep the extra wallpaper as backup. For large windows, patio doors, or many openings, subtracting them gives a more accurate estimate. This tool supports both approaches.
What is pattern repeat and how do I find it?
Pattern repeat is the vertical distance before the design repeats. It’s usually listed on the wallpaper label (e.g., “Repeat: 25 in straight match”). Enter that value so the calculator can estimate how much length you lose when aligning patterns.
Can I use this calculator for murals or digital prints?
Yes, as long as your mural is supplied in rolls or panels with a known width and length. For custom printed murals that are sized exactly to your wall, you may not need a waste margin, but adding a small buffer is still wise.