Calculate Square Feet for Siding

Siding Square Footage Calculator

Wall Dimensions (Feet)

Enter length and height for each wall. Leave blank if not applicable.

Wall 1 Length:

Wall 1 Height:

Wall 2 Length:

Wall 2 Height:

Wall 3 Length:

Wall 3 Height:

Wall 4 Length:

Wall 4 Height:

Gable Dimensions (Feet)

Enter base width and peak height for triangular gables. Leave blank if not applicable.

Gable 1 Base Width:

Gable 1 Peak Height:

Gable 2 Base Width:

Gable 2 Peak Height:

Openings & Waste

Number of Windows:

Avg. Window Width (ft):

Avg. Window Height (ft):

Number of Doors:

Avg. Door Width (ft):

Avg. Door Height (ft):

Waste Factor (%):

Calculation Results:

Net Siding Area: — sq ft

Total Siding Area (with waste): — sq ft

*The 'Total Siding Area' includes the recommended waste factor for cuts and errors.

function calculateSiding() { // Wall 1 var wall1Length = parseFloat(document.getElementById('wall1Length').value) || 0; var wall1Height = parseFloat(document.getElementById('wall1Height').value) || 0; var wall1Area = wall1Length * wall1Height; // Wall 2 var wall2Length = parseFloat(document.getElementById('wall2Length').value) || 0; var wall2Height = parseFloat(document.getElementById('wall2Height').value) || 0; var wall2Area = wall2Length * wall2Height; // Wall 3 var wall3Length = parseFloat(document.getElementById('wall3Length').value) || 0; var wall3Height = parseFloat(document.getElementById('wall3Height').value) || 0; var wall3Area = wall3Length * wall3Height; // Wall 4 var wall4Length = parseFloat(document.getElementById('wall4Length').value) || 0; var wall4Height = parseFloat(document.getElementById('wall4Height').value) || 0; var wall4Area = wall4Length * wall4Height; // Gable 1 (triangular area: 0.5 * base * height) var gable1Width = parseFloat(document.getElementById('gable1Width').value) || 0; var gable1Height = parseFloat(document.getElementById('gable1Height').value) || 0; var gable1Area = 0.5 * gable1Width * gable1Height; // Gable 2 var gable2Width = parseFloat(document.getElementById('gable2Width').value) || 0; var gable2Height = parseFloat(document.getElementById('gable2Height').value) || 0; var gable2Area = 0.5 * gable2Width * gable2Height; // Total Gross Area var totalGrossArea = wall1Area + wall2Area + wall3Area + wall4Area + gable1Area + gable2Area; // Window Area var numWindows = parseFloat(document.getElementById('numWindows').value) || 0; var windowWidth = parseFloat(document.getElementById('windowWidth').value) || 0; var windowHeight = parseFloat(document.getElementById('windowHeight').value) || 0; var totalWindowArea = numWindows * windowWidth * windowHeight; // Door Area var numDoors = parseFloat(document.getElementById('numDoors').value) || 0; var doorWidth = parseFloat(document.getElementById('doorWidth').value) || 0; var doorHeight = parseFloat(document.getElementById('doorHeight').value) || 0; var totalDoorArea = numDoors * doorWidth * doorHeight; // Net Siding Area var netSidingArea = totalGrossArea – totalWindowArea – totalDoorArea; if (netSidingArea < 0) { netSidingArea = 0; // Siding area cannot be negative } // Waste Factor var wasteFactor = parseFloat(document.getElementById('wasteFactor').value) || 0; var totalSidingAreaWithWaste = netSidingArea * (1 + (wasteFactor / 100)); // Display Results document.getElementById('netSidingArea').innerText = 'Net Siding Area: ' + netSidingArea.toFixed(2) + ' sq ft'; document.getElementById('totalSidingArea').innerText = 'Total Siding Area (with waste): ' + totalSidingAreaWithWaste.toFixed(2) + ' sq ft'; }

Understanding Siding Square Footage

Calculating the correct square footage for your home's siding is a crucial first step in any exterior renovation project. Whether you're planning to install vinyl, fiber cement, wood, or metal siding, knowing the precise area helps you accurately estimate material costs, prevent over-ordering (and waste), and ensure you have enough material to complete the job without delays.

Why Accurate Measurement Matters

Cost Control: Siding materials can be expensive. Over-ordering leads to unnecessary expenses, while under-ordering can cause project delays and potentially higher costs if you need to buy small quantities at premium prices.
Material Matching: Siding, especially certain types, can have slight color variations between different production batches. Ordering all your material at once helps ensure a consistent look.
Project Efficiency: Having all materials on hand from the start streamlines the installation process, saving time and labor costs.

How to Measure for Siding

The process involves calculating the total surface area of all exterior walls and gables, then subtracting the area of any openings like windows and doors. Here's a breakdown:

1. Measure Rectangular Walls:

For each rectangular wall, measure its length and height. Multiply these two dimensions to get the square footage of that wall. Repeat for all rectangular walls and sum them up.

Formula: Wall Area = Length × Height

2. Measure Gables (Triangular Sections):

Gables are the triangular sections of wall found at the ends of a pitched roof. Measure the base width of the gable (usually the same as the wall below it) and its vertical height from the base to the peak. The area of a triangle is half its base times its height.

Formula: Gable Area = 0.5 × Base Width × Peak Height

3. Calculate Total Gross Area:

Add up the square footage of all your walls and gables. This gives you the total gross area that needs to be covered.

4. Subtract Openings (Windows and Doors):

Measure the width and height of each window and door. Calculate the area for each opening and then sum them up. Subtract this total opening area from your total gross area to get the net siding area.

Formula: Opening Area = Number of Openings × Width × Height

5. Account for Waste Factor:

It's almost impossible to install siding without some material waste due to cuts, errors, and damaged pieces. A waste factor is an additional percentage added to your net siding area to ensure you have enough material. Common waste factors range from 5% to 15%, depending on the complexity of the house design (more angles, windows, and doors mean more waste) and the type of siding.

Simple rectangular house: 5-10% waste
Complex house with many gables, windows, or angles: 10-15% waste

Formula: Total Siding Area (with waste) = Net Siding Area × (1 + Waste Factor / 100)

Using the Calculator

Our Siding Square Footage Calculator simplifies this process. Simply input the dimensions for your walls, gables, windows, and doors in feet. Don't forget to include a realistic waste factor. The calculator will instantly provide you with both the net siding area and the total siding area including waste, giving you a reliable estimate for your project.

Example Calculation:

Let's consider a house with the following dimensions:

Two walls: 40 ft long x 10 ft high each
Two walls: 30 ft long x 10 ft high each
Two gables: 30 ft wide (base) x 6 ft high (peak) each
Ten windows: 3 ft wide x 4 ft high each
Two doors: 3 ft wide x 7 ft high each
Waste factor: 10%

1. Wall Area:

(40 ft * 10 ft) * 2 = 800 sq ft
(30 ft * 10 ft) * 2 = 600 sq ft
Total Wall Area = 800 + 600 = 1400 sq ft

2. Gable Area:

(0.5 * 30 ft * 6 ft) * 2 = 180 sq ft

3. Total Gross Area:

1400 sq ft (walls) + 180 sq ft (gables) = 1580 sq ft

4. Opening Area:

Windows: 10 windows * (3 ft * 4 ft) = 10 * 12 sq ft = 120 sq ft
Doors: 2 doors * (3 ft * 7 ft) = 2 * 21 sq ft = 42 sq ft
Total Opening Area = 120 + 42 = 162 sq ft

5. Net Siding Area:

1580 sq ft (gross) – 162 sq ft (openings) = 1418 sq ft

6. Total Siding Area (with 10% Waste):

1418 sq ft * (1 + 10/100) = 1418 * 1.10 = 1560.00 sq ft

Using the calculator with these values will yield a net siding area of 1418.00 sq ft and a total siding area (with waste) of 1560.00 sq ft.