How to Calculate Siding Calculator
What is Siding Calculator?
A siding calculator estimates the amount of external cladding material (vinyl, fibre cement, wood) needed for the exterior walls of a building, accounting for overlap, waste, and window/door openings.
Step-by-Step Guide
- 1Calculate total wall area: perimeter × wall height
- 2Subtract all door and window openings
- 3Add 10–15% for waste, cuts, and overlap
- 4For lap siding: exposure width determines how many courses per vertical foot
Worked Examples
Input
House perimeter 40m · Height 5m · 20m² openings
Result
198m² siding + 10% = 218m²
(40×5)−20 = 180m²; ×1.1 = 198