Siding Calculator
Estimate siding coverage, squares, and linear feet for lap, vinyl, or fibre cement — with openings deducted and exposure-based course counts.
Formula and figures last reviewed by the Cosyslabs team · how we verify
Inputs
Result
Coverage needed
1188 ft²
Linear feet
2037
- Net wall area
- 1080 ft²
- Exposure
- 7.00 in per course
- Courses (per 10 ft wall)
- 18
- Waste
- 10%
Waste default: 10% — Ten percent for straightforward walls; 15% where there are many openings, corners, or gable cuts.
Estimates only. Verify with a licensed contractor or supplier before purchasing. Rough Estimator! is not responsible for shortages, overages, or material variances. See our methodology for formulas and sources.
Formula
Net area = gross wall − openings · Coverage = net × (1 + waste) · Linear ft = coverage × 12 ÷ exposure
References
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Frequently asked questions
Measure each wall face, add them, subtract openings over about 10 square feet, then add 10% waste. A 1,200 ft² wall area with 120 ft² of openings needs roughly 1,188 ft² of coverage.
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Cosyslabs. (2026). Siding Calculator. Rough Estimator!. https://roughestimator.com/siding-calculator
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