.roof-calc-header { text-align: center; margin-bottom: 25px; }
.roof-calc-header h2 { color: #2c3e50; margin-bottom: 10px; }
.calc-row { display: flex; flex-wrap: wrap; gap: 20px; margin-bottom: 15px; }
.calc-field { flex: 1; min-width: 200px; }
.calc-field label { display: block; font-weight: 600; margin-bottom: 8px; font-size: 14px; }
.calc-field input, .calc-field select { width: 100%; padding: 12px; border: 1px solid #ccc; border-radius: 6px; font-size: 16px; box-sizing: border-box; }
.calc-btn { width: 100%; background-color: #d35400; color: white; padding: 15px; border: none; border-radius: 6px; font-size: 18px; font-weight: bold; cursor: pointer; transition: background 0.3s; margin-top: 10px; }
.calc-btn:hover { background-color: #e67e22; }
#roof-result { margin-top: 25px; padding: 20px; background-color: #fff; border-radius: 8px; border-left: 5px solid #d35400; display: none; }
.result-item { display: flex; justify-content: space-between; padding: 8px 0; border-bottom: 1px solid #eee; }
.result-item:last-child { border-bottom: none; }
.result-val { font-weight: bold; color: #d35400; }
.roof-article { margin-top: 40px; line-height: 1.6; color: #444; }
.roof-article h3 { color: #2c3e50; margin-top: 25px; }
.roof-article ul { padding-left: 20px; }
function calculateRoofing() {
var length = parseFloat(document.getElementById("roofLen").value);
var width = parseFloat(document.getElementById("roofWid").value);
var pitchMultiplier = parseFloat(document.getElementById("roofPitch").value);
var wasteMultiplier = parseFloat(document.getElementById("wasteFactor").value);
if (isNaN(length) || isNaN(width) || length <= 0 || width <= 0) {
alert("Please enter valid positive numbers for length and width.");
return;
}
// 1. Calculate Base Area
var baseArea = length * width;
// 2. Adjust for Pitch
var actualArea = baseArea * pitchMultiplier;
// 3. Adjust for Waste
var finalArea = actualArea * wasteMultiplier;
// 4. Calculate Squares
var squares = finalArea / 100;
// 5. Calculate Bundles (usually 3 bundles per square)
var bundles = Math.ceil(squares * 3);
// Display Results
document.getElementById("totalArea").innerText = Math.round(finalArea).toLocaleString() + " sq ft";
document.getElementById("totalSquares").innerText = squares.toFixed(2);
document.getElementById("totalBundles").innerText = bundles;
document.getElementById("roof-result").style.display = "block";
// Scroll to result
document.getElementById("roof-result").scrollIntoView({ behavior: 'smooth', block: 'nearest' });
}
Roofing Shingle & Material Calculator
Estimate the amount of shingles and bundles required for your roofing project based on pitch and area.
Flat (0/12)
Low Pitch (2/12)
Low Pitch (3/12)
Standard (4/12)
Standard (5/12)
Moderate (6/12)
Moderate (7/12)
Steep (8/12)
Steep (9/12)
Very Steep (10/12)
Extreme (12/12)
5% (Simple Gable)
10% (Standard Gable)
15% (Hip Roof)
20% (Complex/Valleys)
Estimation Results
Total Roof Area:
0 sq ft
Roofing Squares (100 sq ft):
0
Required Bundles (3 per sq):
0
*Calculations assume standard 3-tab or architectural shingles where 3 bundles equal 1 square.
How to Calculate Roofing Materials Correctly
Estimating roofing materials is more complex than simple floor area because of the roof pitch (the slope) and waste factor. A steeper roof has more surface area than a flat one covering the same footprint. Our calculator uses the pitch multiplier to find the true surface area of your roof.
Understanding Roofing Terminology
- Square: In the roofing industry, one "square" is equal to 100 square feet of roof area.
- Bundle: Shingles are typically sold in bundles. For most standard shingles, 3 bundles are required to cover 1 square.
- Pitch: The ratio of vertical rise to horizontal run. A 4/12 pitch means the roof rises 4 inches for every 12 inches it runs horizontally.
- Waste Factor: This accounts for shingles cut at valleys, hips, and rakes. A simple gable roof usually needs 10% waste, while complex roofs with many dormers may need 20%.
Real-World Example Calculation
Suppose you have a house footprint of 40 feet by 30 feet (1,200 sq ft) and a standard 6/12 pitch roof.
- Footprint Area: 40 x 30 = 1,200 sq ft.
- Pitch Correction: For a 6/12 pitch, the multiplier is 1.118. 1,200 x 1.118 = 1,341.6 sq ft.
- Waste Addition: Adding a 10% waste factor (1,341.6 x 1.10) = 1,475.76 sq ft.
- Final Count: This equals approximately 14.75 squares, which translates to 45 bundles of shingles.