Siding Calculator
Estimate siding squares needed for your walls
Frequently Asked Questions
A square is the standard unit siding is sold in: 100 square feet of wall coverage, regardless of the brand or panel size. It's a holdover from roofing terminology that the siding industry also uses.
Subtract the total area of doors, windows, and other openings from your gross wall area before entering it here — this calculator doesn't automatically detect openings.
10% is a common default for straightforward rectangular walls. Complex walls with lots of corners, gables, or cuts around windows often need 15-20% to account for extra trim waste.
It depends on the manufacturer and panel size — vinyl siding boxes commonly cover about 1-2 squares each, but always check the specific product's coverage-per-box rating before ordering, since it varies.