Wallpaper Calculator with Repeat

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Wallpaper Calculator with Pattern Repeat

Accurately estimate rolls for your project

Calculation Results

Total Rolls Needed: 0

Strips required: 0

Strips per roll: 0

Total area: 0 sq ft

How to Calculate Wallpaper with Pattern Repeat

Calculating wallpaper is more complex than simple area math because of the pattern repeat. When a wallpaper has a design that repeats, you must align the pattern on each adjacent strip. This often results in "wasted" paper at the top or bottom of each strip to ensure the patterns match perfectly.

Understanding the Logic

  • Wall Area: The total square footage of the surface you are covering.
  • Pattern Repeat: The vertical distance between where the design starts and where it repeats. If it's a "straight match," the pattern aligns horizontally across strips.
  • Effective Strip Length: This is the wall height PLUS the pattern repeat. Even if your wall is 8ft, you calculate as if it's 8ft + the repeat distance to account for alignment waste.

Steps for Manual Calculation

  1. Find the number of strips: Divide the total wall width by the roll width. Round up to the nearest whole number.
  2. Find strips per roll: Divide the roll length by (Wall Height + Pattern Repeat). Round down to the nearest whole number.
  3. Find total rolls: Divide the total number of strips needed by the strips per roll. Round up to the nearest whole number.
Pro Tip: Always order 10-15% extra for mistakes, cutting errors, or future repairs. This calculator includes a waste margin field to help you account for this.
function calculateWallpaper() { // Get values var wallW = parseFloat(document.getElementById('wallWidth').value); var wallH = parseFloat(document.getElementById('wallHeight').value); var rollW_in = parseFloat(document.getElementById('rollWidth').value); var rollL_ft = parseFloat(document.getElementById('rollLength').value); var repeat_in = parseFloat(document.getElementById('patternRepeat').value) || 0; var waste = parseFloat(document.getElementById('wasteMargin').value) || 0; // Validation if (isNaN(wallW) || isNaN(wallH) || isNaN(rollW_in) || isNaN(rollL_ft) || wallW <= 0 || wallH rollL_ft && wallH rollL_ft) { alert("The wall height is taller than a single roll of wallpaper."); return; } if (stripsPerRoll <= 0) stripsPerRoll = 1; // 4. Calculate base rolls needed var totalRolls = Math.ceil(stripsNeeded / stripsPerRoll); // 5. Apply waste margin var finalRolls = Math.ceil(totalRolls * (1 + (waste / 100))); // Area Calculation var totalArea = wallW * wallH; // Display results document.getElementById('totalRolls').innerText = finalRolls; document.getElementById('stripsNeeded').innerText = stripsNeeded; document.getElementById('stripsPerRoll').innerText = stripsPerRoll; document.getElementById('totalArea').innerText = totalArea.toFixed(2); document.getElementById('wpResult').style.display = 'block'; }

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