🏘️Siding Calculator
Measure walls and gables to find how many squares of siding you need.
Your walls
Add each wall as a rectangle and each gable as a triangle (base × height).
You'll need about
6.82 squares
620 sq ft to cover · 682 sq ft with 10% waste (1 square = 100 sq ft)
sq ft net
620
sq ft to order
682
squares
6.82
🛒 Shopping list
- Siding6.82 squares
Siding is sold by the square — 100 sq ft. Most suppliers round up to whole boxes or bundles.
How it works
Add the area of each wall (length × height) and each gable triangle (base × height ÷ 2), subtract doors and windows, then add waste. Squares = square feet ÷ 100.
Worked example
Walls of 40 × 8 and 30 × 8 ft plus a 30 × 8 ft gable = 680 sq ft, minus 60 sq ft of openings = 620 sq ft. With 10% waste that's 682 sq ft, or 6.82 squares.
Questions people ask
100 sq ft of coverage.
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Last updated October 8, 2026. These results are friendly estimates to help you plan — always double-check before buying or making big decisions.