How this calculator works
The calculator multiplies total wall length by average wall height, then subtracts openings to estimate net siding area. Siding squares are net area divided by 100 square feet. Panel count is based on panel coverage with waste added. Corner trim is estimated from corner count multiplied by wall height.
Example: 160 feet of wall length at 9 feet high gives 1,440 square feet before openings. After subtracting 220 square feet, the net wall area is 1,220 square feet, or 12.20 siding squares. With 10% waste and 10 square feet per panel, the estimate rounds to 135 panels.