Simple (Single Story, Easy Access)
Average (Two Story, Normal Access)
Complex (Difficult Access, Many Valleys)
Please enter a valid roof area.
Estimated Roof Size
0 sq ft
(Includes 10% Waste Factor)
Material Cost
$0.00
Labor Installation
$0.00
Tear-Off & Disposal
$0.00
Total Estimated Cost
$0.00
*Estimates vary by region and contractor. Always get 3 professional quotes.
function calculateRoofCost() {
// 1. Get Inputs
var areaInput = document.getElementById('roofArea').value;
var pitchMult = parseFloat(document.getElementById('roofPitch').value);
var matCostPerSqFt = parseFloat(document.getElementById('roofMaterial').value);
var laborCostPerSqFt = parseFloat(document.getElementById('laborCost').value);
var isTearOff = document.getElementById('tearOff').checked;
var errorDiv = document.getElementById('errorDisplay');
var resultsDiv = document.getElementById('resultsArea');
// 2. Validation
if (areaInput === "" || isNaN(areaInput) || parseFloat(areaInput) <= 0) {
errorDiv.style.display = "block";
resultsDiv.style.display = "none";
return;
}
errorDiv.style.display = "none";
var baseArea = parseFloat(areaInput);
// 3. Logic & Formulas
// Calculate Actual Roof Surface Area (Base * Pitch)
// Add 10% for waste (cuts, hips, valleys, ridges)
var wasteFactor = 1.10;
var totalRoofSqFt = baseArea * pitchMult * wasteFactor;
// Material Cost
var totalMaterialCost = totalRoofSqFt * matCostPerSqFt;
// Labor Cost (Applied to the actual surface area work)
var totalLaborCost = totalRoofSqFt * laborCostPerSqFt;
// Tear Off Cost (Applied to surface area)
// Average tear off and disposal is roughly $1.50 – $2.00 per sq ft
var tearOffRate = 1.75;
var totalTearOffCost = 0;
if (isTearOff) {
totalTearOffCost = totalRoofSqFt * tearOffRate;
}
// Total Cost
var grandTotal = totalMaterialCost + totalLaborCost + totalTearOffCost;
// 4. Update DOM
// Format Currency Helper
function fmtMoney(num) {
return "$" + num.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}
document.getElementById('resSize').innerText = Math.round(totalRoofSqFt) + " sq ft";
document.getElementById('resMaterial').innerText = fmtMoney(totalMaterialCost);
document.getElementById('resLabor').innerText = fmtMoney(totalLaborCost);
document.getElementById('resTearOff').innerText = isTearOff ? fmtMoney(totalTearOffCost) : "$0.00";
document.getElementById('resTotal').innerText = fmtMoney(grandTotal);
// Show results
resultsDiv.style.display = "block";
}
Understanding Your Roof Replacement Quote
Replacing a roof is one of the most significant investments a homeowner will make. Use our Roofing Cost Calculator to get a realistic baseline of what you should expect to pay before talking to contractors. This tool breaks down the essential components of a roofing bid: materials, labor, pitch complexity, and tear-off fees.
Key Factors That Influence Roofing Costs
When calculating the price of a new roof, several variables come into play beyond just the square footage of your home:
Roof Pitch (Steepness): A steeper roof is more dangerous and difficult to work on. It requires more safety equipment (harnesses) and time, significantly increasing the labor cost multiplier.
Material Choice: Asphalt shingles are the most common and affordable option in the US. However, premium materials like metal, clay tile, or slate can cost 3x to 5x more per square foot but last significantly longer.
Tear-Off: If your home already has two layers of shingles, or if the existing roof is damaged, contractors must strip the old material. This adds labor and dumpster disposal fees to the total.
Waste Factor: Professional roofers calculate 10-15% extra material to account for cutting shingles to fit valleys, hips, and ridges. Our calculator automatically applies a 10% waste factor for accuracy.
Material Price Breakdown
Understanding the cost per "square" (a roofing term for 100 sq ft) is vital. Here are general estimates used in this calculator:
3-Tab Asphalt: The budget-friendly option, typically lasting 15-20 years.
Architectural Shingles: Thicker and more dimensional, these are the standard for modern homes and offer better wind resistance.
Metal Roofing: highly durable and energy-efficient, often lasting 50+ years.
How to Measure Your Roof
If you don't know your roof's exact square footage, you can estimate it based on your home's footprint (length x width). However, remember to account for the slope. A flat roof has the same area as the footprint, but a high-pitch roof has significantly more surface area. Use the "Pitch" dropdown in the calculator to adjust for this geometry automatically.
Note: This calculator provides an estimate. Unexpected structural damage (rotted decking) found after tear-off can increase final project costs.