Siding Calculator

Work out how many squares and panels of siding a house needs, including the gable ends, less doors and windows.

From the foundation to the soffit.
Doors, windows and garage doors.
12′ 6″ is common for vinyl.
Visible height per panel: 8″ for double 4″ vinyl.
$
Fractions and decimals both work.
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Squares
Wall area
Gable area
Net area
Panels
Starter strip
Cost

Project List

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NameNet AreaSquaresPanelsCostRemove

How to Figure Siding

Siding is sold by the square, 100 square feet of wall. Multiply the house's perimeter by the wall height, add the triangular gable ends, and subtract doors and windows. Each gable is a triangle: half its width times its height, and the height comes from the roof pitch.

Walls = perimeter × height   Each gable = width × (width ÷ 2 × pitch ÷ 12) ÷ 2
Squares = (walls + gables − openings) × (1 + waste) ÷ 100

Each panel covers its length times its exposure, the part that shows once it's installed.

Worked Example

Tips

Many pros skip subtracting small windows, treating the extra as waste; subtract large openings like garage doors. Order trim separately: outside corner posts for each corner, J-channel around windows and doors and along the soffit, and starter strip along the bottom. Leave expansion gaps at the ends of vinyl panels and nail in the center of the slots so they can move.