Free siding calculator estimates vinyl siding area, boxes and project cost. Enter wall dimensions and waste allowance for accurate material needs.
Siding is sold by the box, and each box covers a fixed area - but the math only gets you partway. You also need trim (J-channel) around the wall perimeter and every door and window opening. This calculator estimates both the panel boxes and the trim length from your wall size and opening counts.
Enter the wall length and height plus the number of doors and windows. The result gives the gross wall area, the net area after openings, boxes to order and the J-channel trim length for a complete material list.
Siding only covers the solid wall, so openings are subtracted first. The calculator uses typical sizes - about 1.9 m² per door and 1.5 m² per window - and then adds a waste allowance for cuts around the openings and at corners.
A standard box of vinyl siding covers roughly 200 sq ft (about 18.6 m²) of wall, which is 2 roofing-style squares. Coverage varies by brand and profile, so adjust the coverage field to match your product's label.
Measure the gable as a triangle: base x height / 2 gives the area, then add it to the rectangular walls before entering the total. The waste allowance will cover the angled cuts at the roofline.