Building a shed can be a rewarding project, whether for storage, a workshop, or a garden retreat. The cost, however, can vary significantly based on size, materials, labor, and additional features. This calculator provides an estimate by breaking down the potential expenses involved in constructing a typical shed.
Key Factors Influencing Shed Cost:
Dimensions: The length, width, and height of your shed are primary drivers of cost. Larger sheds require more materials and labor.
Roof Design: The complexity of the roof, including its pitch and style (e.g., gable, gambrel, skillion), affects material quantities and construction difficulty.
Materials: The type of siding (e.g., wood, vinyl, metal), roofing material (e.g., shingles, metal panels), and quality of lumber used will impact the overall price.
Foundation: The chosen foundation method – from simple pier blocks to a full concrete slab – adds to the cost and affects durability.
Labor: Whether you're a DIYer or hiring professionals, labor costs are a significant component. Professional installation will be more expensive.
Features & Finishes: Doors, windows, shelving, insulation, electrical wiring, paint, stain, and trim all add to the final price.
Permits: Depending on your location and the size of the shed, you may need to obtain building permits, which incur fees.
How the Calculator Works:
This calculator estimates your shed's cost by considering several key components:
Wall Surface Area: Calculates the total square footage of the shed's walls. This is based on the perimeter of the shed multiplied by the wall height.
Roof Surface Area: Estimates the area of the roof. This is more complex and depends on the roof pitch. A steeper pitch means a larger roof surface area than a flatter pitch for the same shed footprint. The calculation uses the shed's length, width, and the specified roof pitch to determine the sloped roof area.
Total Material Area: Sums up the wall and roof surface areas to get an estimate of the primary material coverage needed.
Material & Labor Costs: Multiplies the total material area by the cost per square foot for materials and labor, respectively.
Foundation Cost: Adds the cost of the selected foundation type, which can be a fixed price or a cost per square foot depending on the option.
Additional Features: Includes the specified costs for doors, windows, and any finishing touches like paint or trim.
Permit Fees: Adds the cost of necessary building permits.
Total Estimated Cost: Sums all the calculated costs to provide a final estimated price for your shed project.
Disclaimer: This calculator provides an estimate for informational purposes only. Actual costs may vary based on specific material choices, local market prices, contractor bids, and unforeseen construction challenges. It's always recommended to get detailed quotes from suppliers and contractors for the most accurate pricing.
function calculateShedCost() {
var shedLength = parseFloat(document.getElementById("shedLength").value);
var shedWidth = parseFloat(document.getElementById("shedWidth").value);
var wallHeight = parseFloat(document.getElementById("wallHeight").value);
var roofPitchInput = document.getElementById("roofPitch").value.trim();
var materialCostPerSqFt = parseFloat(document.getElementById("materialCostPerSqFt").value);
var laborCostPerSqFt = parseFloat(document.getElementById("laborCostPerSqFt").value);
var foundationType = document.getElementById("foundationType").value;
var doorCost = parseFloat(document.getElementById("doorCost").value);
var windowCost = parseFloat(document.getElementById("windowCost").value);
var trimPaintStain = parseFloat(document.getElementById("trimPaintStain").value);
var permitCost = parseFloat(document.getElementById("permitCost").value);
var resultValueElement = document.getElementById("result-value");
var resultDetailsElement = document.getElementById("result-details");
// Validate inputs
if (isNaN(shedLength) || shedLength <= 0 ||
isNaN(shedWidth) || shedWidth <= 0 ||
isNaN(wallHeight) || wallHeight <= 0 ||
isNaN(materialCostPerSqFt) || materialCostPerSqFt < 0 ||
isNaN(laborCostPerSqFt) || laborCostPerSqFt < 0 ||
isNaN(doorCost) || doorCost < 0 ||
isNaN(windowCost) || windowCost < 0 ||
isNaN(trimPaintStain) || trimPaintStain < 0 ||
isNaN(permitCost) || permitCost 0) {
var slopeRatio = Math.sqrt(Math.pow(rise, 2) + Math.pow(run, 2)) / run;
var rafterLength = (shedWidth / 2) * slopeRatio; // Length of one side of the roof
// For a gable roof, the roof area is approximately the length of the shed * (2 * rafterLength)
// This is a simplified estimation; actual roof geometry can be more complex.
// A more precise method might consider overhangs and roof type (gable, gambrel, etc.)
// For simplicity, we'll use the rafter length and shed length.
// We estimate roof area as (length + overhang) * (2 * rafter length + overhang)
// For a basic calculation, let's use length * 2 * rafterLength as a proxy.
// More realistically, let's consider one slope: shedLength * rafterLength
// And multiply by 2 for a gable roof, adding a bit for width projection.
var roofPitchFactor = Math.sqrt(1 + Math.pow(rise / run, 2));
// Area of one side of the roof = length * (width/2 * roofPitchFactor)
// Total roof area for gable roof = 2 * (shedLength * (shedWidth / 2) * roofPitchFactor)
// This simplifies to shedLength * shedWidth * roofPitchFactor, but this is not quite right.
// A better approximation: shedLength * (shedWidth/2 * sqrt(1 + (rise/run)^2)) * 2
// which is shedLength * shedWidth * sqrt(1 + (rise/run)^2). Let's check this logic.
// Let's refine the roof area calculation.
// Consider one slope of the roof. The horizontal span is shedWidth / 2.
// The length along the slope (rafter length) is (shedWidth / 2) * sqrt(1 + (rise/run)^2).
// The area of one side of the roof is shedLength * rafter length.
// Total roof area (gable roof) = 2 * shedLength * (shedWidth / 2) * sqrt(1 + (rise/run)^2)
// = shedLength * shedWidth * sqrt(1 + (rise/run)^2)
// This is still underestimating as it doesn't account for the 'run' in the area.
// A common way to estimate roof area for pitch is: Area = Base Area * (pitch factor)
// Pitch factor = sqrt(1 + (rise/run)^2) is more related to rafter length.
// Let's try a more common practical estimation:
// Area = (shedLength + overhang) * (shedWidth/2 * sqrt(1 + (rise/run)^2) + overhang) * 2
// For simplicity, let's use:
var roofSlopeLength = (shedWidth / 2) * Math.sqrt(1 + Math.pow(rise / run, 2));
// Area of one side of the roof = shedLength * roofSlopeLength
// Total roof area (gable) = 2 * shedLength * roofSlopeLength
roofArea = 2 * shedLength * roofSlopeLength;
// Add a small allowance for overhangs, say 0.5ft on each side if not specified
var overhang = 0.5;
roofArea = (shedLength + 2*overhang) * (roofSlopeLength + overhang) * 2;
// Revert to simpler for clarity if complex formula is error prone
roofArea = 2 * shedLength * ((shedWidth / 2) * Math.sqrt(1 + Math.pow(rise / run, 2)));
// A very common simplified estimation: Base Area * 1.2 for moderate pitch
// If pitch is very low or very high, this factor changes.
// Let's stick to the geometric calculation using rise/run.
var baseRoofArea = shedLength * shedWidth;
var roofPitchFactor = Math.sqrt(1 + Math.pow(rise / run, 2)); // This is the factor for slope length over horizontal run
roofArea = baseRoofArea * roofPitchFactor; // This is still a simplification but more common.
} else {
throw new Error("Invalid roof pitch format.");
}
} else {
// Assume a flat roof or default if format is wrong
roofArea = shedLength * shedWidth; // Flat roof area
roofPitchInput = "Assumed Flat"; // Indicate assumption
}
// Handle cases where pitch might be invalid but we need a calculation
if (roofArea <= 0) {
roofArea = shedLength * shedWidth; // Fallback to base area if pitch calculation fails
}
// Total primary surface area (walls + roof)
var totalSurfaceArea = wallArea + roofArea;
// Calculate material and labor costs for walls and roof
var materialCost = totalSurfaceArea * materialCostPerSqFt;
var laborCost = totalSurfaceArea * laborCostPerSqFt;
// Calculate foundation cost
var foundationCost = 0;
var foundationArea = shedLength * shedWidth;
switch (foundationType) {
case "concrete_slab":
foundationCost = foundationArea * parseFloat(document.getElementById("foundationType").options[document.getElementById("foundationType").selectedIndex].text.match(/(\d+\.?\d*)-\$(\d+\.?\d*)\/sq ft/)[1] || 7.5); // Mid-range estimate
break;
case "gravel_base":
foundationCost = foundationArea * parseFloat(document.getElementById("foundationType").options[document.getElementById("foundationType").selectedIndex].text.match(/(\d+\.?\d*)-\$(\d+\.?\d*)\/sq ft/)[1] || 3); // Mid-range estimate
break;
case "pier_blocks":
foundationCost = parseFloat(document.getElementById("foundationType").options[document.getElementById("foundationType").selectedIndex].text.match(/\$(\d+)-\$(\d+) total/)[1] || 100); // Mid-range estimate
break;
case "none":
default:
foundationCost = 0;
break;
}
// Total estimated cost
var totalCost = materialCost + laborCost + foundationCost + doorCost + windowCost + trimPaintStain + permitCost;
resultValueElement.textContent = "$" + totalCost.toFixed(2);
var details = `
Breakdown:
– Wall Area: ${wallArea.toFixed(2)} sq ft
– Roof Area (Pitch: ${roofPitchInput}): ${roofArea.toFixed(2)} sq ft
– Total Surface Area (Walls + Roof): ${totalSurfaceArea.toFixed(2)} sq ft
– Materials Cost: $${materialCost.toFixed(2)}
– Labor Cost: $${laborCost.toFixed(2)}
– Foundation Cost (${foundationType}): $${foundationCost.toFixed(2)}
– Door Cost: $${doorCost.toFixed(2)}
– Window Cost: $${windowCost.toFixed(2)}
– Trim/Paint/Stain: $${trimPaintStain.toFixed(2)}
– Permit Cost: $${permitCost.toFixed(2)}
`;
resultDetailsElement.innerHTML = details;
}