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Measure Exterior Walls
Enter the width and height of every wall receiving siding. The calculator multiplies each width by its corresponding height.
Siding Calculator
Estimate the net siding area, siding squares, panels, cartons, waste allowance, and material cost for your home improvement project.
Enter Project Measurements
Add each exterior wall separately for a more accurate estimate.
Simple Process
How the Siding Calculator Works
The calculator measures the exterior surface, subtracts openings, adds installation waste, and converts the final area into common siding units.
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Subtract Openings
Add the combined square footage of doors and windows so that these areas are removed from the gross exterior measurement.
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Review Materials
Select your waste allowance and product coverage to estimate siding squares, panels, boxes, and total material cost.
How Much Siding Do You Need?
Estimating siding begins with the total square footage of the exterior walls. Each rectangular wall is calculated by multiplying its width by its height. Triangular gable sections are calculated separately because their area is one-half of the base multiplied by the height.
After combining all wall and gable areas, subtract the square footage occupied by doors and windows. The remaining measurement is the net siding area.
What Is a Square of Siding?
One siding square covers 100 square feet of exterior surface. For example, a project requiring 1,500 square feet of material equals 15 siding squares before accounting for waste.
Why Is a Waste Allowance Important?
Some material is lost when panels are cut around corners, windows, doors, rooflines, and utility penetrations. A waste allowance also provides replacement pieces for damaged panels or measurement differences.
- Simple rectangular homes may need approximately 5% waste.
- Average projects commonly use a 10% waste allowance.
- Complex walls and multiple gables may require 15% or more.
Common Siding Materials
This calculator can be used for vinyl, fiber cement, engineered wood, aluminum, steel, composite, and wood siding. Enter the actual coverage shown on your product package for the most accurate box and panel estimate.
Helpful Answers
Frequently Asked Questions
Learn how to measure siding area and plan material quantities before placing an order.
Multiply the width of each exterior wall by its height, combine the wall areas, add any gable area, and subtract the total area of doors and windows.
One square of siding covers 100 square feet. A project requiring 2,000 square feet equals 20 siding squares before adding a waste allowance.
Yes. Large doors and windows should normally be subtracted from the gross wall area. Small openings may sometimes be left in the estimate to provide additional cutting material.
A 10% waste allowance is common for standard projects. Simple buildings may need less, while complex designs, steep gables, and numerous openings may require 15% or more.
Yes. Enter the square-foot coverage printed on one carton. The calculator divides the waste-adjusted siding area by the carton coverage and rounds up to the next whole box.
No. The displayed estimate covers siding material based on the price you enter. Labor, insulation, house wrap, trim, fasteners, removal, disposal, and taxes are not included.
Yes. The area calculation works for most siding materials. Update the box and panel coverage fields using the actual specifications of your selected product.