Estimated Roof Size (including waste factor):0 sq. ft.
Material Cost Estimate:0
Labor & Installation Estimate:0
Tear-off & Disposal:0
Total Estimated Cost: $0
*Estimates include a 10% waste factor for cuts and overlaps.
function calculateRoofingCost() {
// 1. Get Input Values
var footprintInput = document.getElementById("homeFootprint").value;
var pitchMultiplier = parseFloat(document.getElementById("roofPitch").value);
var materialPricePerSqFt = parseFloat(document.getElementById("roofMaterial").value) / 100; // Value is per square (100sqft), converting to sqft but actually value in option is usually per square price in dollars.
// Correction: The options values like "450" represent $4.50 * 100? No, usually prices are per "Square" (100 sq ft).
// Let's interpret values in option: 450 = $4.50/sqft * 100. Wait, 450 is cents? Or Dollars?
// Let's redefine logic: 450 cents = $4.50.
// Let's treat the value in 'value' attribute as CENTS per square foot to be precise, or just DOLLARS per square (100sqft).
// Let's say option value="450″ means $450 per SQUARE (100 sq ft installed).
// That equals $4.50 per sq ft installed.
// Let's stick to the visual text in option: "450" = $4.50/sq.ft. So value is CENTS per sq ft.
var materialCostCents = parseFloat(document.getElementById("roofMaterial").value);
var materialCostDollars = materialCostCents / 100;
var includeTearOff = document.getElementById("includeTearOff").checked;
// 2. Validation
if (!footprintInput || footprintInput <= 0) {
alert("Please enter a valid home footprint area in square feet.");
return;
}
var footprint = parseFloat(footprintInput);
// 3. Logic & Calculation
// Add Overhang/Eaves estimation (approx 10% of footprint)
var eavesFactor = 1.10;
var baseArea = footprint * eavesFactor;
// Apply Pitch Multiplier to get actual surface area
var roofSurfaceArea = baseArea * pitchMultiplier;
// Add Waste Factor (Standard 10% for cuts/ridges)
var wasteFactor = 1.10;
var totalBillableArea = roofSurfaceArea * wasteFactor;
// Calculate Costs
// Material Cost is embedded in the "Installed Price" usually, but we break it down for show.
// Let's assume the selection is TOTAL installed cost per sq ft.
// To display split, we assume Material is 45% and Labor is 55% of the base install price.
var totalBaseInstallCost = totalBillableArea * materialCostDollars;
var splitMaterial = totalBaseInstallCost * 0.45;
var splitLabor = totalBaseInstallCost * 0.55;
// Tear Off Calculation
var tearOffCost = 0;
if (includeTearOff) {
// $1.50 per sq ft for tear off
tearOffCost = totalBillableArea * 1.50;
}
var totalCost = totalBaseInstallCost + tearOffCost;
// 4. Formatting Output
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
minimumFractionDigits: 0,
maximumFractionDigits: 0,
});
// 5. Update DOM
document.getElementById("resultsArea").style.display = "block";
document.getElementById("displayArea").innerText = Math.round(totalBillableArea).toLocaleString() + " sq. ft.";
document.getElementById("displayMaterial").innerText = formatter.format(splitMaterial);
document.getElementById("displayLabor").innerText = formatter.format(splitLabor);
if (includeTearOff) {
document.getElementById("tearOffRow").style.display = "flex";
document.getElementById("displayTearOff").innerText = formatter.format(tearOffCost);
} else {
document.getElementById("tearOffRow").style.display = "none";
}
document.getElementById("displayTotal").innerText = formatter.format(totalCost);
}
Understanding Your Roofing Estimate
Calculating the cost of a new roof involves more than just buying shingles. The total price is heavily influenced by the "pitch" (steepness) of your roof, the complexity of the design, and the material you choose. This calculator provides a comprehensive estimate by factoring in waste, labor, and optional tear-off costs.
Key Factors Affecting Roof Cost
1. Roof Pitch (Steepness)
The angle of your roof determines how much material is needed and how difficult the installation will be.
Low Slope: Easier to walk on, safer for crews, generally cheaper labor.
Steep Pitch: Requires safety harnesses and more staging equipment. This increases labor costs and time.
Because a steep roof creates a triangle with a longer hypotenuse, the actual surface area is significantly larger than your home's footprint.
2. Roofing Materials
Materials vary wildly in price and longevity:
Asphalt Shingles: The most common and affordable option. Architectural shingles offer better durability and aesthetics than standard 3-tab shingles.
Metal Roofing: Higher upfront cost but can last 50+ years. Standing seam metal is the gold standard for durability.
Tile & Slate: Premium materials that are heavy and require a reinforced roof structure, costing significantly more.
3. Tear-Off and Disposal
If you are replacing an existing roof, the old material must be removed. This is labor-intensive and requires dumpster fees. While layering new shingles over old ones is legal in some areas, a complete tear-off allows inspectors to check the wood decking for rot.
What is a "Square"?
In the roofing industry, you will often hear contractors refer to "Squares." One Square equals 100 square feet of roof area. If your roof is 2,000 sq. ft., you need 20 Squares of material.
How to Measure Your Roof Area
The most accurate way is to measure the actual roof, but you can estimate it from the ground. Take the length and width of your home's ground floor to get the footprint. Our calculator automatically applies a multiplier based on the pitch you select to estimate the actual surface area of the roof slopes.
Average Cost Per Square Foot (2024)
While prices vary by region, here are typical installed cost ranges:
Asphalt: $3.50 – $5.50 per sq. ft.
Metal: $9.00 – $14.00 per sq. ft.
Tile: $12.00 – $20.00 per sq. ft.
Note: These prices usually include materials, labor, and overhead.