How much siding do I need for my house?

Calculate total wall area: measure each wall (length × height), add areas together, then subtract windows (15 sq ft each) and doors (21 sq ft each). Add gable areas if applicable (width × peak height ÷ 2). Siding is sold in 'squares' — 1 square = 100 sq ft. Divide net wall area by 100 for squares needed. Add 10-15% for waste. A typical 1,500 sq ft house needs 15-20 squares of siding depending on window count and gable configuration.

How do I calculate siding for gable ends?

Gable area = Base Width × Peak Height ÷ 2 (for a triangle). For a standard gable: measure the width of the house at the eave line and the height from the eave to the ridge peak. If the gable has a different pitch on each side, calculate each triangle separately. Most houses have two gable ends. Don't forget to subtract any gable windows. Gable areas typically add 200-400 sq ft to a house's siding needs.

How much waste factor should I add for siding?

Standard rectangular walls: 10% waste. Houses with many windows, doors, and corners: 12-15%. Complex shapes, dormers, and bay windows: 15-20%. Board and batten or vertical siding: 10-12%. Diagonal or patterned installation: 15-20%. First-time DIY installers should add an extra 5%. Scrap pieces from cuts can often be used on shorter wall sections above/below windows.

Siding Calculator — Free Squares, Panels & Cost Estimator for Vinyl, Wood & Fiber Cement 2026 | AllInOneTools

🏠 Construction & Home Improvement

Siding Calculator

Calculate squares, panels, trim, and total cost for vinyl, wood, fiber cement, metal, and engineered wood siding. Supports gable ends, window/door deductions, and waste factors.

Wall Dimensions (total exterior)

Total Wall Perimeter

Wall Height (eave)

Windows

windows

Doors (including garage)

doors

Gable Ends (optional)

Gable Width

Gable Peak Height

Number of Gable Ends

gables

Siding Material

Siding Type

Waste Factor

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Material List

💰

Cost Estimate

📝 Step-by-Step Calculation

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Related Construction & Home Tools

Siding Calculator: The Complete Guide to Estimating Squares, Panels, and Cost

Replacing or installing new siding is one of the most impactful exterior home improvements — it transforms curb appeal, improves energy efficiency, and protects the structure from weather damage. Getting the material estimate right prevents expensive shortages (different dye lots can cause color mismatch) and reduces waste on a project that typically costs $8,000–$25,000 for an average home.

The Siding Formula

Wall Area = Perimeter × Wall Height
Gable Area = Gable Width × Peak Height ÷ 2 × Number of Gables
Gross Area = Wall Area + Gable Area
Deductions = (Windows × 15 sq ft) + (Doors × 21 sq ft)
Net Area = Gross − Deductions
With Waste = Net Area × (1 + Waste%)
Squares = Net Area with Waste ÷ 100

Worked Example — Medium Home (Vinyl Siding)

Perimeter: 160 ft, Wall height: 9 ft
Wall area: 160 × 9 = 1,440 sq ft
Gables: 2 × (30 × 6 ÷ 2) = 180 sq ft
Gross: 1,440 + 180 = 1,620 sq ft
Deductions: 10 windows (150) + 3 doors (63) = 213 sq ft
Net: 1,620 − 213 = 1,407 sq ft
With 10% waste: 1,407 × 1.10 = 1,548 sq ft (15.5 squares)
Vinyl cost: 1,548 × $3.50 = $5,418 materials

Siding Types Compared

Type	Cost/Sq Ft (Installed)	Lifespan	Maintenance
Vinyl	$3-$8	20-40 years	None (wash only)
Fiber Cement (Hardie)	$6-$13	30-50 years	Paint every 15 yrs
Wood (Cedar)	$6-$12	20-40 years	Stain/paint 3-7 yrs
Engineered Wood	$5-$10	20-30 years	Paint every 10 yrs
Metal (Steel/Alum)	$5-$12	40-60 years	None (minimal)
Board and Batten	$7-$15	20-50 years	Varies by material

Pro Tip — Order from the Same Production Run

Like wallpaper, siding colors can vary slightly between production runs. Order all material from the same lot to ensure consistent color across your house. Order 10-15% extra — using scrap from cuts on shorter sections reduces waste significantly. Store siding flat and protected from direct sun before installation (vinyl warps in heat, fiber cement can absorb moisture).

Critical — House Wrap and Flashing First

Always install house wrap (Tyvek or equivalent) and proper window/door flashing BEFORE siding. Water that gets behind siding (and it will) needs a drainage plane to redirect it out. Improperly flashed windows are the #1 source of water damage in residential construction. Use self-adhering flashing tape at all window and door openings, with proper shingling (upper pieces overlapping lower pieces). This is code-required virtually everywhere.

Frequently Asked Questions

How much siding do I need?▼

Perimeter × wall height + gable areas − windows (15 sq ft each) − doors (21 sq ft each) = net area. Divide by 100 for squares. Add 10-15% waste. A typical 1,500 sq ft house needs 15-20 squares. Our calculator handles all measurements automatically.

How much does siding cost?▼

Vinyl: $3-$8/sq ft installed. Fiber cement: $6-$13. Wood: $6-$12. Engineered wood: $5-$10. Metal: $5-$12. Materials are ~40-50% of installed cost. A 2,000 sq ft exterior: vinyl $6,000-$16,000, fiber cement $12,000-$26,000 installed.

What is a square of siding?▼

One "square" = 100 sq ft of coverage. Industry standard measurement for siding (and roofing). A carton of vinyl siding typically covers about 100 sq ft (1 square). Fiber cement planks are sold per piece — calculate coverage from individual plank dimensions.

What type of siding is best?▼

Depends on budget and priorities. Cheapest: vinyl (zero maintenance). Most popular upgrade: fiber cement (wood look, fireproof, 30-50 yr). Most beautiful: real wood cedar (high maintenance). Most durable: metal (40-60 yrs). Best value: engineered wood (wood look, moderate cost/maintenance).

How do I calculate gable areas?▼

Gable area = Width × Peak Height ÷ 2. Peak height is measured from the eave line to the ridge. A 30 ft wide gable with 6 ft peak = 30 × 6 ÷ 2 = 90 sq ft. Most houses have 2 gable ends (180 sq ft total). Don't forget to subtract gable windows.

How much waste should I add?▼

Standard rectangle: 10%. Many windows/corners: 12-15%. Complex shapes/dormers: 15-20%. Board and batten: 10-12%. DIY first-timers: add extra 5%. Scraps from longer pieces can be used on shorter sections above/below windows to reduce actual waste.

Do I need house wrap under siding?▼

Yes — always. House wrap (Tyvek, felt paper) is code-required under virtually all siding. It stops water while letting vapor escape. Install over sheathing, tape all seams, flash windows and doors, then install siding. Some insulated siding has built-in WRB but most doesn't.