Boneyard Tools

Siding Calculator: Squares and Panels

Work out how much siding the exterior walls need. Enter the gross wall area, subtract doors and windows, set a waste allowance, and add a panel coverage for a panel count.

How to estimate siding for walls

  1. Enter the gross wall area in square feet for all walls.
  2. Subtract the square footage of doors and windows.
  3. Set a waste allowance and panel coverage to read off squares and panels.

Examples

1500 sq ft walls, 150 sq ft openings, 14 sq ft panels

Walls 1500, openings 150, 10% waste, panel covers 14 sq ft
1350 sq ft net, 14.85 squares, 107 panels

Frequently asked questions

What is a square of siding?

A square of siding covers 100 square feet of wall. Siding is often ordered and priced by the square, so converting the net wall area into squares makes it easy to compare products and quotes.

Do I subtract windows and doors?

Yes. Subtract the area of doors and large windows so you are not paying to cover openings. Small windows are sometimes left in as extra waste, which simplifies cutting around the frames.

How much siding waste should I add?

Around 10 percent suits a plain wall. Walls with many corners, gables, dormers or angled cuts waste more, so 15 percent is common on a complex elevation with lots of trim and returns.

What panel coverage should I enter?

Use the coverage printed on the box for the exact product. Many vinyl panels cover roughly 14 square feet each, but lap siding, board and batten and shake panels vary widely, so check the label.

Does this include trim, starter or corner posts?

No. This counts field panels only. J-channel, starter strip, corner posts, soffit and fascia are ordered separately based on the length of the eaves, rakes, corners and openings on the house.

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