Vinyl Siding Calculator

Estimating vinyl siding involves calculating the total surface area to be covered, subtracting areas that won't be sided (like windows and doors), and adding a waste factor for cuts and mistakes. The result is typically expressed in "squares," where one square equals 100 square feet.

1. Measure Wall Areas: Calculate the area (Length × Height) of each rectangular wall section to be sided. Measure gables (triangles) as 0.5 × Base × Height. Sum these areas.
2. Measure Deduction Areas: Calculate the area (Width × Height) of all openings like windows, doors, and large vents that will not be covered by siding. Sum these deduction areas.
3. Calculate Net Area: Subtract the total deduction area from the total wall area: `Net Area = Total Wall Area - Total Deduction Area`.
4. Add Waste Factor: Increase the net area by a percentage (commonly 10-15%) to account for cuts, overlaps, and potential errors: `Total Sq Ft Needed = Net Area × (1 + Waste % / 100)`.
5. Convert to Squares: Divide the total square footage needed by 100 to get the number of squares to order: `Squares Needed = Total Sq Ft Needed / 100`.

• Wall Areas: Enter the length and height (in feet) for each distinct wall section you need to cover with siding. Use the 'Add Another Wall Area' button for multiple sections or complex house shapes.
• Deduction Areas: Enter the width and height (in feet) for openings like windows and doors. The calculator will subtract these areas from the total wall area.
• Waste Factor (%): The percentage of extra material to add to account for cutting, fitting around obstacles, and potential mistakes. 10% is a common starting point.

In the siding industry, materials are often sold by the "square." A square is a unit of area equivalent to 100 square feet(e.g., a 10 ft by 10 ft area).

Knowing the total squares needed helps you determine how many boxes or bundles of siding to purchase, as packaging usually indicates coverage in squares.

The waste factor is crucial for ensuring you have enough siding to complete the job without running short. It accounts for material lost during:

• Cutting: Siding panels need to be cut to fit wall lengths, around windows/doors, and under eaves.
• Angles & Gables: Cutting siding for angled walls like gables generates more waste than straight cuts.
• Overlap: Proper installation requires panels to overlap, consuming slightly more material than the visible area.
• Mistakes: Allows a buffer for mis-cuts or damaged pieces.

A higher waste factor (15% or more) is recommended for complex layouts or if you are less experienced.

This calculator estimates the siding panels only. Remember to also purchase:

• Starter Strips: Used to secure the first course of siding at the bottom of walls.
• J-Channel: Trim used around windows, doors, and where siding meets soffit or roofs.
• Corner Posts: Used for inside and outside corners where walls meet.
• Soffit & Fascia: Materials for covering eaves and roof edges (if part of the project).
• Underlayment/House Wrap: Weather-resistant barrier applied before siding.
• Fasteners: Siding nails or screws appropriate for vinyl siding installation.
• Utility Trim / Undersill Trim: Used at the top of walls or under windowsills.

Quantities for these accessories need to be calculated separately based on your specific house dimensions and features.