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Wall & Gable Siding Area Budget Calculator

Estimate siding coverage and cost for a rectangle or triangular gable, with openings and waste.

  • Formula & worked example
  • Private in your browser
  • No signup
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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Edit a calculated value to solve backwards, or lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

A 10 × 3 meter wall minus one 2 m² door and two 1 m² windows leaves 26 m². A 10% allowance raises coverage to 28.6 m²; at 15 per m², the material budget is 429.

Net area = shape factor × width × height − door area − window area; order area = net area × (1 + waste fraction); price = order area × area price

Worked example

Enter these known values and leave the other values blank.

I'm putting siding on a...
wall
Height
3 m
Width
10 m
Number of doors
1
Door height
200 cm
Door width
100 cm
Number of windows
2
Window height
100 cm
Window width
100 cm
Waste factor
10 %
Unit price
15 USD / m²
Total door area
2 m²
Total window area
2 m²
Siding needed
28.6 m²
Total price
429 USD

Assumptions and limitations

  • Waste is added to net coverage. Whole package or panel quantities may require further rounding.
  • Labor, trim, fasteners, delivery and taxes are excluded unless included in the entered area price.

Common questions

How is the gable height measured?

Use the perpendicular height from the triangle base to its peak, not the sloping roof edge. The gable model uses half of width times height. Enter only openings within that surface. It calculates coverage area, not individual panel layouts or trim lengths.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

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