Siding Calculator

Estimate siding square footage, subtract windows and doors, and calculate siding squares required. For simple wall measurement, try our Wall Area Calculator.

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Siding Needed: —
Formula:
Wall Area = Length × Height
Net Area = Wall Area − Openings
Adjusted Area = Net Area × (1 + Waste%)
Squares = Adjusted Area ÷ 100
Example:
100 ft × 8 ft = 800 ft²
Minus 120 ft² openings = 680 ft²
10% waste → 748 ft²
748 ÷ 100 = 7.48 squares

Frequently Asked Questions

What is a siding square?

One siding square equals 100 square feet.

How much waste should I add?

Typically 5–15% depending on house complexity.

Should I subtract windows and doors?

Yes, subtract large openings to get accurate material estimates.