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Calculation Machine

Siding Calculator

Squares and boxes of siding from wall area minus openings.

Reviewed by the Calculation Machine team · How we check our maths

Your values

ⓘ Live results

Results
Siding squares
14.19
Net wall area
1,290 sq ft
Boxes (2 squares each)
8
Starter strip
150 ft
J-channel
322 ft (estimate)
Material cost
$3,263.70

Working

  1. 1150 x 9 + 120 - 180 = 1,290 ft2 -> 14.19 squares

Quick answer

Siding area = wall area minus openings, plus waste. One square covers 100 sq ft; vinyl usually ships two squares per box.

The formula

squares = (wall area - openings) x (1 + waste) / 100

Worked example

Worked example

Using the values the calculator loads with.

Inputs

  • Perimeter of house150 ft
  • Wall height9 ft
  • Gable area120 sq ft
  • Window and door area180 sq ft
  • Waste10 %
  • Cost per square230 $

Result

  • Siding squares14.19
  • Net wall area1,290 sq ft
  • Boxes (2 squares each)8
  • Starter strip150 ft
  • J-channel322 ft (estimate)
  • Material cost$3,263.70

How to use the Siding Calculator

  1. 1Walk the perimeter and measure the wall height to the soffit.
  2. 2Add gable triangles (base x height / 2 each) and subtract windows and doors.
  3. 3Add 10% waste, more if the house has many corners and dormers.

Frequently asked questions

Should I subtract every window?

Subtract anything larger than about 10 sq ft. Leaving small openings in the total covers the offcuts you will lose around them anyway.

How much extra should I order?

10% on a simple box-shaped house, up to 15 to 20% on a complex facade with dormers, bays and steep gables.

About this calculator