Wallpaper Calculator
Rolls of wallpaper a room needs by wall size and roll coverage.
Input sheet
DIY at your own risk. Calcora's calculators and guides are general estimates and information only — not professional, engineering, legal, or safety advice. Always verify local building codes and permit requirements, and hire a licensed pro for electrical, gas, plumbing, structural, or any work you're not fully comfortable doing yourself.
Wallpaper is unforgiving — run short on a patterned roll mid-wall and a new batch may not match. This calculator builds in a pattern-matching allowance so you buy enough rolls the first time.
How it works
Perimeter times wall height for area, plus 15% for pattern matching, divided by the usable coverage of one roll.
Wall area is perimeter times height, then padded by 15% for pattern matching, and divided by the usable coverage of one roll. The 15% is critical: patterns repeat, and you trim material off each strip to line up the design, so a roll never covers its full nominal area.
Roll coverage varies widely by product, so the calculator uses the figure you enter. A 'double roll' covers more than a single, and the usable area is always less than the printed roll size once you account for the pattern repeat.
Rolls = (perimeter × height × 1.15) ÷ roll coverage, rounded up.
Worked examples
A 12 ft × 12 ft room with 8 ft walls and 28 sq ft rolls. → 16 rolls.
Perimeter = 2 × 24 = 48 ft × 8 = 384 sq ft × 1.15 = 442 ÷ 28 = 15.8, rounded up to 16 rolls.
A 10 ft × 14 ft room with 9 ft walls and 56 sq ft double rolls. → 9 rolls.
Perimeter = 2 × 24 = 48 ft × 9 = 432 sq ft × 1.15 = 497 ÷ 56 = 8.9, rounded up to 9 rolls.
Tips & gotchas
- Buy every roll from the same batch or run number — color shifts subtly between batches and a mismatched strip is impossible to hide.
- Large pattern repeats waste more material; the 15% allowance is a minimum, so add more for bold, widely-spaced designs.
- Keep an extra roll for repairs — wallpaper lines get discontinued, and patching a damaged section years later needs a match.
- Measure the actual wall, not the floor — tall ceilings dramatically increase the area and the roll count.
FAQ
Why do I need 15% extra for wallpaper?
Because patterns must line up between strips, you trim material off each drop to match the repeat. That trimmed material isn't usable, so the roll covers less than its nominal area — the allowance accounts for it.
What's the difference between a single and double roll?
A double roll is one continuous roll with the square footage of two singles, sold to reduce seams and waste. Enter your roll's actual coverage so the count is right either way.
Should I account for the pattern repeat size?
Yes — a large repeat wastes more per strip. The built-in 15% covers a typical repeat; for bold, widely-spaced patterns, plan for more and confirm the repeat length on the product.
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