Wallpaper Calculator
Estimate wallpaper for a room. Enter the wall dimensions and the coverage per roll, and we'll add a waste allowance for pattern matching and trimming.
Example: with Room length 12 ft · Room width 12 ft · Wall height 9 ft · Coverage per roll 28 sq ft → Rolls needed: 18 rolls.
- Wall area432 sq ft
- Area incl. waste497 sq ft
Computed by the calculator below using its default values. Change any input to see your own numbers.
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Check it outWhy waste matters with wallpaper
Wallpaper needs more waste than paint because patterns must line up between strips. A 10–15% allowance is typical, and large pattern repeats can require 20% or more. Buy all rolls from the same batch number so colors match, and keep a spare roll for future repairs.
How it’s calculated
Wall area = 2 × (length + width) × height. Rolls = area × (1 + waste) ÷ coverage per roll.
Results update as you type and are estimates, not professional advice — verify important decisions with a qualified professional.
Common mistakes
- Under-allowing waste for pattern matching.
- Mixing roll batches and getting color shifts.
Frequently asked questions
How much waste should I add?
10–15% for small or random patterns; 20%+ for large repeating patterns that need careful matching.
This counts the whole wall — what about doors and windows?
Leaving them in adds a built-in cushion. For big openings, you can subtract their area to refine the estimate.
What is a pattern repeat?
The vertical distance before a pattern restarts. Larger repeats waste more paper aligning strips.