Siding Calculator
Squares and boxes of vinyl siding from your home's wall area.
Input sheet
DIY at your own risk. Calcora's calculators and guides are general estimates and information only — not professional, engineering, legal, or safety advice. Always verify local building codes and permit requirements, and hire a licensed pro for electrical, gas, plumbing, structural, or any work you're not fully comfortable doing yourself.
Siding is estimated in 'squares' — 100 sq ft units — and vinyl typically ships in boxes covering two squares. This calculator turns your home's perimeter and wall height into squares and boxes, with waste built in for cuts, corners, and overlaps.
How it works
Wall area = perimeter × wall height, plus waste. Siding is sold in squares (100 sq ft); a typical vinyl box covers 2 squares.
The base area is perimeter × wall height, treating the house as a simple band of wall. Gables sit on top of that: each gable triangle is ½ × its width × the peak's rise, added to the total. The waste allowance covers end cuts, lock overlaps, and the pieces you scrap around openings.
Estimators typically do not subtract windows and doors on siding jobs — the offcuts created cutting around openings roughly cancel the area removed, and the margin protects against a short order. Only subtract very large openings like a garage door.
Wall area = perimeter × wall height × (1 + waste); squares = area ÷ 100; boxes = area ÷ 200 (rounded up).
Worked examples
A 140 ft-perimeter single-story home with 9 ft walls and 10% waste. → About 13.9 squares — 7 boxes of vinyl.
140 × 9 = 1,260 sq ft; × 1.1 = 1,386; ÷ 100 ≈ 13.9 squares; ÷ 200 rounds up to 7 boxes.
A 160 ft-perimeter home with 10 ft walls and 10% waste. → 17.6 squares — 9 boxes.
160 × 10 × 1.1 = 1,760 sq ft = 17.6 squares; 1,760 ÷ 200 = 8.8, rounded up to 9 boxes.
Tips & gotchas
- Order all boxes from one dye lot — vinyl color varies subtly between production runs and a mid-wall shade shift is permanent.
- Bump waste to 15% on houses with many corners, dormers, or gables; simple rectangles can get by at 5–10%.
- Trim pieces (J-channel, corner posts, starter strip) are a separate order counted in linear feet — measure openings and corners for those.
FAQ
Do I subtract windows and doors?
Installers usually don't — the offcuts around openings roughly cancel the opening area, and the margin covers mistakes.
How do I figure gables?
Each gable is a triangle: half its width times the rise from eave to peak. Add every gable's area to the wall total before applying waste.
What does a square of vinyl cost?
Material alone runs roughly $90–110 per square for mid-grade vinyl; installed prices are several times that. Insulated and premium profiles cost more.
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