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🏠 Siding Calculator

Calculate siding materials needed for vinyl, fiber cement, wood, and other siding types.

Quick Formula​

Square Footage​

Wall Area = (Length + Width) × 2 × Height
Siding Needed = Wall Area × Waste Factor

Deductions​

Net Area = Wall Area - (Windows + Doors)

Common Siding Types​

Vinyl Siding​

ProfileCoverage per SquareWaste Factor
Single 4"100 sq ft5-7%
Double 5"100 sq ft5-7%
Triple 6"100 sq ft5-7%

Accessories:

  • Starter strip: 1 per wall
  • J-channel: Perimeter + windows/doors
  • Corner posts: 1 per corner
  • Soffit: If applicable

Fiber Cement Siding​

SizeCoverageWaste Factor
8-1/4" × 12'8.25 sq ft5-10%
12" × 12'12 sq ft5-10%

Accessories:

  • Trim boards: Perimeters, corners
  • Fasteners: Per manufacturer specs
  • Caulk: Seams and joints

Wood Siding​

TypeCoverageWaste Factor
Lap sidingVaries by width10-15%
Shingles2-3 sq ft per bundle10-15%
Board & battenVaries10-15%

Common Calculations​

Example 1: Vinyl Siding​

House: 40' × 30' × 10' high Windows/Doors: 200 sq ft

Calculation:

  • Perimeter: (40 + 30) × 2 = 140 linear feet
  • Wall area: 140 × 10 = 1,400 sq ft
  • Net area: 1,400 - 200 = 1,200 sq ft
  • With 7% waste: 1,200 × 1.07 = 1,284 sq ft
  • Squares: 1,284 ÷ 100 = 12.84 squares

Accessories:

  • Starter: 140 LF
  • J-channel: 140 + 50 (windows) = 190 LF
  • Corners: 4 corners × 10' = 40 LF

Example 2: Fiber Cement​

Wall: 50' × 10' = 500 sq ft Windows: 50 sq ft

Calculation:

  • Net area: 500 - 50 = 450 sq ft
  • Panels (8-1/4" × 12'): 450 ÷ 8.25 = 54.5 panels
  • With 10% waste: 54.5 × 1.10 = 60 panels

Waste Factors​

ApplicationWaste Factor
Simple rectangular5-7%
Windows/doors7-10%
Complex shapes10-15%
Gables/angles15-20%
Measure Twice

Siding mistakes are expensive. Measure carefully, account for all openings, and order extra for waste.