Calculate wallpaper rolls with pattern repeat and waste accounted for.
Formula: Wall area = perimeter × height − (doors × 20 + windows × 15). Add waste for pattern repeat: 0" repeat = 10%, 12" = 15%, 24"+ = 25%. Rolls = ceil(adjusted area ÷ usable per roll).
| Repeat | Waste Factor | Example |
|---|---|---|
| 0" (random) | 10% | Stripes, textures |
| 6-12" | 15% | Small florals |
| 18-24" | 20% | Medium patterns |
| 25"+ | 25-30% | Large murals |
Tip: Buy all rolls from the same dye lot. Keep unopened rolls for potential returns — most stores accept returns within 30-90 days.