🏡 Vinyl Siding Calculator

What Is a "Square" of Siding?

Siding — like roofing — is sold by the square, which is simply 100 square feet of coverage. Vinyl siding typically comes in boxes containing 2 squares (200 sq ft), so a house needing 16 squares takes 8 boxes.

The estimate works like this:

• Wall area = house perimeter × wall height. For a 40 × 28 ft house with 9-ft walls: 2 × (40 + 28) × 9 = 1,224 sq ft.
• Gable area = ½ × gable width × peak height, per gable. Two 28-ft wide gables rising 6 ft add 168 sq ft.
• Subtract openings: this calculator deducts an average of 15 sq ft per window/door. (Standard window ≈ 12–15 sq ft, entry door ≈ 20 sq ft.)

Don't Forget the Accessories

The panels are only part of the order. Every vinyl siding job also needs trim pieces, and they're a common budget surprise:

• Starter strip: one run around the entire base of the house — equal to your perimeter in linear feet.
• J-channel: frames every window, door, and roofline transition. Rough rule: 20 linear feet per window/door opening.
• Corner posts: one per outside corner, in wall-height lengths.
• Utility trim & finish trim: under windows and at the top course.

Use our Linear Footage Calculator to total up trim runs before you order.

Vinyl vs. Fiber Cement vs. Engineered Wood

• Vinyl ($3–$8/sq ft installed): Cheapest, zero painting, DIY-possible. Can crack in extreme cold and fade in strong sun. The default choice for budget re-sides.
• Fiber cement ($6–$13/sq ft installed): Fire-resistant, crisp painted look, 30–50 year lifespan. Heavy, requires special cutting tools (silica dust), and needs repainting every 12–15 years.
• Engineered wood ($5–$10/sq ft installed): Real-wood look, lighter and easier to cut than fiber cement, strong warranties. Must be kept painted and properly flashed.

Frequently Asked Questions

How many squares of siding do I need for a 2,000 sq ft house?

Living area doesn't determine siding — wall area does. A typical 2,000 sq ft two-story house has roughly 1,500–1,800 sq ft of net wall area, or 15–18 squares (8–9 boxes of vinyl). Use the calculator above with your actual dimensions.

How much does vinyl siding cost in 2026?

Material runs $90–$250 per square depending on panel thickness and style ($150–$200 is typical mid-grade). Installed by a contractor, expect $3–$8 per square foot including accessories and house wrap.

Should I subtract windows and doors from a siding estimate?

Yes for large openings (garage doors, sliders, picture windows). Many estimators leave standard windows in as built-in waste allowance. This calculator subtracts 15 sq ft per opening and then adds your waste percentage back — a balanced approach.

How much waste should I add for siding?

10% for a simple gable-roof rectangle. Go to 15% for hip roofs, dormers, bays, and complex layouts with many cuts.

Can I install vinyl siding myself?

It's one of the more DIY-able exterior projects — the panels lock and nail with basic tools. The rules that matter: nail loose (panels must slide), leave ¼" expansion gaps at trim, and always start with a dead-level starter strip.