Project Parameters
Average wall height from foundation to roofline.
Sum of all exterior wall lengths around your house.
Peak height of triangular gable ends (enter 0 if hip roof).
Combined base width of all triangular gable ends.
Total area of windows and doors to subtract (typical home: 100-200 sq ft).
Instant Estimate
Siding Squares (100 sq ft)
Most siding is quoted and sold by the square (100 sq ft).
Bundles Needed (~200 sq ft/bundle)
Standard vinyl packaging covers 2 squares per carton.
Net Wall Surface (Before Waste)
Gable Triangle Area
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Guide
How to calculate siding for your home
Siding is measured in square feet and ordered in 'squares' — where one square equals 100 square feet of finished coverage. A typical 1,500 sq ft single-story home requires 14–18 squares of siding once windows and doors are deducted and a standard 10% cutting waste factor is added.
Measure Rectangular Walls
Measure the perimeter of the home and multiply by the average wall height (from foundation to the soffit).
Add Triangular Gable Ends
Calculate each gable triangle using ½ × base × peak height. Add all gables to your total.
Subtract Doors & Windows
Measure openings (standard entry door is 21 sq ft, average window is 15 sq ft) and deduct their total area.
Add 10% Waste Factor
Multiply the net square footage by 1.10. For complex houses with lots of valleys and dormers, use 15%.
Mathematics
Formulas used
Wall Area
Wall Height × Total PerimeterThe rectangular surface of exterior walls around the footprint.
Gable Triangle Area
½ × Gable Base Width × Gable Peak HeightFor two identical gables, width × height yields total triangle area.
Order Quantity
(Gross Area − Openings) × 1.10 / 100Net square footage plus 10% cutting waste, divided into 100 sq ft squares.
Answers & FAQ
Frequently asked questions
How do I calculate how much siding I need?▼
Multiply your total perimeter by the wall height, add any triangular gable areas, subtract window and door openings, and then multiply by 1.10 to add a 10% waste buffer. Divide by 100 to get the number of siding squares.
What is a 'square' of siding?▼
In exterior construction, one square is exactly 100 square feet of coverage. Siding, roofing, and house wrap are predominantly sold and estimated in squares.
How many squares of siding do I need for a 2,000 sq ft house?▼
A typical 2,000 sq ft two-story house has about 1,800 to 2,300 sq ft of exterior wall surface. With deductions and 10% waste, you will usually need between 18 and 22 squares.
What is the cheapest siding material in 2026?▼
Standard vinyl siding remains the most affordable choice at $3 to $8 per square foot in materials. Engineered wood (LP SmartSide) ranges from $5 to $11, while fiber cement (Hardie board) is $5 to $13.
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