Siding Calculator
Estimate siding squares from your wall area.
Enter your total exterior wall area, subtract doors and windows, and get the amount of siding in squares including a waste allowance. Siding, like roofing, is sold and estimated by the square (100 sq ft).
How it works
Subtract openings from the wall area, add a waste allowance, then divide by 100 for squares. Allow extra for trim, corners, and the angled cuts under gables — 10% is a reasonable starting point for straightforward walls.
Frequently asked questions
How much siding do I need?
Subtract doors and windows from the total wall area, add 10% waste, then divide by 100 for squares. A 1,200 sq ft wall with 120 sq ft of openings is about 11.9 squares.
What is a siding square?
A square covers 100 square feet of wall. Siding is sold and priced by the square, the same way roofing is.
How much waste should I add for siding?
About 10% for simple walls, more for homes with many corners, gables, and windows that require angled cuts.
Is this calculator free and private?
Yes. Every CubicCabin calculator runs entirely in your browser, so the numbers you enter are never uploaded or stored. There's no sign-up, no limits, and it keeps working even if you lose connection after the page loads.