Siding Calculator

Use Siding Calculator

Figures update as you type. Nothing you enter leaves this tab, and no values are stored.

Total wall length (ft)Wall height (ft)

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About Siding Calculator

A siding calculator estimates the wall area to be clad and converts it into squares, the 100-square-foot unit siding is sold and estimated in. From the total wall length and height it gives the area and the squares, the figures a supplier needs to quote materials for cladding a house. The tool multiplies length by height for the gross wall area and expresses it in squares. In practice you subtract large openings - windows and doors - and add about 10% for waste, trim and the overlap most siding profiles need, so treat the square figure as the gross area before those adjustments. Gables add triangular areas that are easy to forget; measure and add them separately. Different siding materials have different coverage and waste factors, so confirm with your supplier.

Using Siding Calculator

Group walls with the same height, total their length in feet and enter that height. For different elevations, calculate each rectangle separately and record the areas.
Divide square feet by 100 to read siding squares. The displayed figure is gross rectangular coverage; large openings and triangular gables are not entered automatically.
Reconcile the measured area with the manufacturer's effective coverage per panel or carton. Allow for cut lengths and overlaps according to the chosen profile before rounding to full packs.

Where siding calculator helps

Cladding a wall

120 ft of wall at 9 ft high is 1,080 ft² - about 11 squares before deducting openings.

Before you use the result

A wall group 120 ft long and 9 ft high gives 1080 square feet, or 10.8 squares. Subtracting a 6 by 7 ft opening leaves 1038 square feet before layout allowances; keep that adjustment in your worksheet because this form has no openings field.
A gable triangle with a 20 ft base and 6 ft height adds 60 square feet: half the base times the height. Adding it as a full rectangle would double that portion of the estimate.
Trim, starter pieces, corners, fasteners and moisture-control layers are separate materials. Effective coverage can differ from a board's physical width because of laps. Check the product coverage and the planned cut layout instead of ordering directly from gross area alone.

Questions about Siding Calculator

What is a square of siding?

100 square feet of wall coverage. Siding is estimated and often priced by the square, so converting your wall area to squares is how you order it.

Is my data saved or uploaded?

No. Siding Calculator calculates the result entirely in this browser; the values you enter are not stored or sent to a server.