Siding Calculator
Estimate how much siding a house needs. Enter the total wall perimeter, the wall height and the area of doors and windows — the calculator returns coverage in "squares" (100 sq ft) plus the net wall area.
How it works
Gross wall area = perimeter × height. Net area = gross − openings. Squares = net area × (1 + waste%) ÷ 100. One "square" of siding covers 100 sq ft.
Frequently asked questions
What is a "square" of siding?
A square is the trade unit for 100 square feet of wall coverage. Siding is ordered and priced by the square.
How much siding waste should I add?
Plan on about 10% waste for straight walls and up to 15% for homes with lots of corners, gables or angles. This calculator adds your chosen percentage.
Do I subtract windows and doors?
Yes — subtract the total area of openings from the gross wall area. Enter that combined area and the calculator removes it before adding waste.
Related calculators
Estimates are for planning only. Material yields, densities and code requirements vary — confirm quantities with your supplier and local building code before ordering.