dopecalc

Wallpaper Calculator

Determine how many rolls of wallpaper you need for a wall. Accounts for wall dimensions, roll size, and pattern repeat to minimize waste and ensure a professional result.

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Enter 0 if there is no pattern repeat

About this Calculator

Determine how many rolls of wallpaper you need for a wall. Accounts for wall dimensions, roll size, and pattern repeat to minimize waste and ensure a professional result.

Formula & Calculations

Formula

Wall Area = Length × Height; Strips per roll = (Roll Length) / (Wall Height + Pattern Repeat); Total strips = Wall Width / Roll Width; Rolls = Total strips / Strips per roll (round up)
Where:
  • Wall L=Length (width) of the wall in feet
  • Wall H=Height of the wall in feet
  • Roll W=Width of a single wallpaper roll in inches
  • Roll L=Length of a single wallpaper roll in feet
  • Repeat=Pattern repeat distance in inches (enter 0 for no pattern)

Assumptions

  • Standard wallpaper roll dimensions are approximately 20.5 inches wide by 33 feet long (double roll).
  • Pattern repeat adds extra length per strip to align the pattern.
  • Partial strips are counted as full strips since you cannot piece wallpaper horizontally.
  • Does not account for doors, windows, or other openings.

Calculation Examples

Example 1

Inputs:Wall: 12 ft wide × 8 ft tall, Roll: 20.5 in × 33 ft, 0 in repeat
Result:8 strips needed, 1 strip per roll, 8 rolls

Wall width in inches = 144. Strips needed = 144 / 20.5 ≈ 7.02, round up to 8. Strips per roll = 33 / 8 = 4.125, floor to 4. Rolls = 8/4 = 2.

Example 2

Inputs:Wall: 15 ft wide × 9 ft tall, Roll: 20.5 in × 33 ft, 6 in repeat
Result:9 strips (15 ft / 20.5 in ≈ 8.78 → 9), 3 strips/roll, 3 rolls

With 6" repeat, effective strip length = 9 ft + 0.5 ft = 9.5 ft. Strips per roll = 33/9.5 ≈ 3.47, floor to 3. Rolls = 9/3 = 3.

Frequently Asked Questions

What is a pattern repeat and why does it matter?

A pattern repeat is the vertical distance between matching points in the wallpaper design. You need extra length on each strip so the pattern aligns with adjacent strips, which increases material usage.

What are standard wallpaper roll dimensions?

A standard North American double roll is approximately 20.5 inches wide by 33 feet long. European rolls are typically 20.5 inches wide by 33 feet. Single rolls (half length) also exist.