Siding Calculator
Calculate how many squares of siding you need.
Enter wall dimensions, windows, and doors to get an accurate material estimate.
Siding Needed
Siding is sold in “squares” where 1 square = 100 sq ft (or approximately 9.29 m²).
Net Wall Area = (Wall Length × Wall Height) - Window Area - Door Area
Squares = Net Wall Area / 100 sq ft
Unit conversions:
Imperial: Squares = Net Area (sq ft) / 100Metric: Squares = Net Area (m²) / 9.29
Standard deductions:
- Window (average): 15 sq ft (1.4 m²) each
- Door (standard): 20 sq ft (1.86 m²) each
- Garage door: 120 sq ft (11.15 m²) each
Waste factors by siding type:
- Vinyl siding: 10% waste
- Wood lap siding: 15% waste
- Fiber cement: 10–12% waste
- Board and batten: 12–15% waste
Tips:
- Measure each wall separately for best accuracy
- Remember to include gable ends (triangle area = base × height / 2)
- Always order extra for future repairs