Siding Coverage Calculator
Calculate the total siding material needed for your project based on wall dimensions, openings, and waste factor.
Enter each wall section as: width x height (in feet)
Enter each opening as: width x height (in feet). Leave blank if none.
Enter each gable as: base x height (in feet). Leave blank if none.
Typical: 10% for standard installs, 15% for diagonal/complex patterns.
1 square = 100 sq ft. Most siding is sold by the square.
Formulas Used
Total Wall Area = Σ (Wall Width × Wall Height)
Gable Area = Σ (0.5 × Base × Height) — triangular gable ends
Net Area = Total Wall Area + Gable Area − Σ Opening Areas
Area with Waste = Net Area × (1 + Waste% ÷ 100)
Squares Needed = Area with Waste ÷ Coverage per Square
Order Quantity = ⌈Squares Needed × 2⌉ ÷ 2 — rounded up to nearest 0.5 square
Assumptions & References
- 1 square = 100 sq ft (industry standard unit for siding).
- Gable ends are treated as triangles: Area = 0.5 × base × height.
- A 10% waste factor is standard for straight runs; use 15% for diagonal or complex patterns (Vinyl Siding Institute).
- Openings (doors, windows) are fully subtracted; some contractors subtract only 50% of openings under 20 sq ft — adjust accordingly.
- Order quantity is rounded up to the nearest 0.5 square to avoid under-ordering.
- Coverage per square may vary by product; verify with your supplier's spec sheet.
- Reference: Vinyl Siding Institute (vinylsiding.org); NAHB Remodeling Cost Data.