GlenCalc

Siding calculator

Siding is sold by the square (100 sq ft). Enter the house’s perimeter and wall height, the gables, and the openings.

Pick the conditions closest to your job. Each adds the allowance shown for offcuts, breakage and uneven ground. Choose Custom to enter your own.

Your answer

Siding16.17 squares
Lap siding pieces231
Area with waste1,617 sq ft

Worked out in your browser. Nothing you type is sent to a server.

How we worked it out

Updated as you change the numbers.

  1. Walls = 160 × 9; each gable = width × height ÷ 2; less openings; plus 10% waste.
  2. Pieces = area ÷ (exposure × piece length).
A room's walls with length, width and wall height marked, and a door and windowlengthwidthheight

Method and assumptions

Wall area is the perimeter × the eave height, plus the triangular gable ends, less windows and doors. Each lap board covers its exposure (not its full width) times its length. Trim, J-channel and corners are extra.

Questions

How many squares of siding for a 40 × 40 house with 9 ft walls?

About 16.2 squares with two 30 × 7 ft gables, 180 sq ft of openings and 10% waste.

Sources

Method and figures checked on . Every worked answer on this page is covered by an automated test. Found a mistake? Tell us.

Embed this calculator on your site

Free to use. Paste this where you want the calculator; it runs in your visitors’ browsers, sets no cookies and sends nothing to us.

Related calculators