DIY Cost Tools
Siding Calculator
Estimate net exterior wall area, siding squares, full cartons, waste, and material cost. Use supplier coverage and pricing for the exact siding profile you plan to install.
Measure: Measure the total exterior perimeter, average wall height, gable areas, doors, and windows.
How the estimate works: The calculator uses your measurements, unit conversions, waste allowance, and product coverage to create a planning quantity. Review the formula shown above, then read the matching guide below before ordering. See How Our Calculators Work for assumptions and limitations.
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Follow the siding manufacturer’s fastening, expansion-gap, flashing, and weather-barrier instructions. Read our advertising disclosure.
How this calculator works
Net wall area = perimeter × average height + gables − doors − windows. Purchase area adds waste; one siding square equals 100 square feet.
Measure each elevation
For better accuracy, calculate the front, rear, and each side separately. Add triangular gables and other wall sections, then subtract large openings. Small openings are sometimes left in the estimate because their material becomes useful for cuts.
Complete-system costs
Siding projects also require starter strips, corners, trim channels, flashing, housewrap, fasteners, sealants, scaffolding, delivery, and disposal. Confirm the carton coverage and exposure for your exact product.
Read the complete how to estimate siding: wall area, squares, and waste.
Siding-area example
A 40-by-30-foot rectangular house has a 140-foot perimeter. At 9 feet high, the gross wall area is 1,260 square feet. If measured windows and doors total 180 square feet, the preliminary net area is 1,080 square feet. Adding 10% for cuts, laps, damage, and repairs produces 1,188 square feet, or 11.88 siding squares. Round to the exact carton’s installed coverage.
Use exposed coverage, not nominal board size
Measure gables, dormers, bump-outs, garage walls, and different materials separately. Overlap, profile, orientation, trim, corners, starter strips, J-channel, soffit, fascia, mounting blocks, and manufacturer packaging affect the order. Housewrap, flashing, sheathing repair, fasteners, removal, disposal, staging, and access equipment are separate quantities. Water-management and fastening details should follow the manufacturer and local requirements.