How to use this siding calculator
Estimate siding square footage, boxes, gables, openings, waste, trim, labor, and project cost.
Formula
Wall area = perimeter × height + triangular gable area − openings. Order area = net area × (1 + waste %). Cartons = order area ÷ carton coverage, rounded up.Worked example
Example: A 40 × 28 ft rectangular home has a 136 ft perimeter. At 18 ft average wall height, gross rectangular wall area is 2,448 sq ft before gables and openings.
Accuracy and limitations
Complex elevations, multiple story heights, bump-outs, soffit, fascia, corners, starter strips, and unusually large openings require elevation-by-elevation measurements.