*This is a ballpark estimate. Local labor rates and debris removal fees may vary.
How to Calculate Roofing Costs
Calculating the cost of a new roof involves more than just measuring the footprint of your home. To get an accurate estimate, you must account for the roof pitch, which increases the total surface area, and the complexity of the architectural design.
Understanding "Squares"
In the roofing industry, materials are measured in "squares." One square equals 100 square feet of roof surface. Most contractors will quote you based on the price per square, which typically includes both labor and material.
Realistic Cost Example
If you have a 2,000 sq. ft. ranch-style home with a moderate pitch (1.15 multiplier) and choose Architectural Shingles ($6.50/sq. ft. installed), the calculation looks like this:
Base Area: 2,000 sq. ft.
True Surface Area: 2,000 x 1.15 = 2,300 sq. ft. (23 Squares)
Total Estimate: 2,300 x $6.50 = $14,950
Key Factors Affecting Your Quote
Tear-off Fees: Removing 2 or more layers of old shingles increases labor and disposal costs.
Decking Replacement: If the wood underneath (sheathing) is rotted, expect to pay $70-$100 per 4×8 sheet.
Permits: Local municipal fees vary significantly by zip code.
Ventilation: Adding ridge vents or attic fans can add $500 – $1,500 to the total.
function calculateRoofCost() {
var groundArea = parseFloat(document.getElementById("roofArea").value);
var pitch = parseFloat(document.getElementById("roofPitch").value);
var materialPrice = parseFloat(document.getElementById("materialType").value);
var complexity = parseFloat(document.getElementById("complexity").value);
if (isNaN(groundArea) || groundArea 1.1 ? 1.15 : 1.10;
var totalSurfaceArea = surfaceArea * wasteFactor;
// 3. Squares calculation
var squares = totalSurfaceArea / 100;
// 4. Cost Logic
// materialPrice in the dropdown is actually the "Installed Price per sq ft" base
// We split it roughly 40% materials / 60% labor for the breakdown
var totalCost = totalSurfaceArea * materialPrice * complexity;
var laborCost = totalCost * 0.60;
var materialCost = totalCost * 0.40;
// Display Results
document.getElementById("resSurfaceArea").innerText = Math.round(totalSurfaceArea).toLocaleString() + " sq ft";
document.getElementById("resSquares").innerText = squares.toFixed(1);
document.getElementById("resLabor").innerText = "$" + laborCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("resMaterials").innerText = "$" + materialCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("resTotal").innerText = "$" + totalCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("roof-result").style.display = "block";
}