Siding Calculator

Use our free Siding Calculator to estimate siding squares, panels, and trim needed for your project. Enter wall dimensions, gables, windows, and doors, and this calculator will return a clear order recommendation with a waste allowance factored in.

Siding Material Calculator

1
Walls
2
Gables
3
Openings
4
Soffit/Fascia
5
Material & Waste
6
Results

Wall Sections

Enter the dimensions of each wall section. Add multiple sections for complex walls.

Label Width Height Unit Inside Corners Outside Corners Action

Gable Sections

Enter the dimensions of triangular gable sections. Leave empty if no gables.

Label Base Height Unit Action

Windows & Doors

Enter window and door openings to subtract from total area.

Type Label Width Height Unit Action

Soffit & Fascia

Enter soffit and fascia measurements if applicable.

Material Profile & Waste

Select your siding material and adjust waste percentage if needed.

Extra material to account for cuts and mistakes (typically 10-15%)

Calculation Results

Your siding material estimate based on the provided measurements.

Order Recommendation: Order 4 squares (400 sq ft)
300
Wall Area (sq ft)
75
Gable Area (sq ft)
12
Openings Area (sq ft)
0
Soffit Area (sq ft)
363
Raw Area (sq ft)
399.3
Adjusted Area (sq ft)
4
Siding Squares
20
Panels Needed

Trim & Accessories

Item Quantity Unit
Outside Corner Posts 2 pieces
Inside Corner Posts 0 pieces
Starter Strips 30 linear ft
J-Channel 60 linear ft
Fascia 0 linear ft

How to Measure for Siding

Proper measurement is crucial for an accurate siding estimate. Follow these steps to measure your home correctly:

Step 1: Measure Wall Sections

Break down your home’s exterior into rectangular wall sections. Measure the width and height of each section. For walls with different heights, measure each height section separately.

Step 2: Measure Gable Sections

For triangular gable areas, measure the base (width) and height from the base to the peak. If your gable has multiple sections, measure each separately.

Step 3: Measure Openings

Measure all windows and doors that won’t be covered with siding. Record the width and height of each opening to subtract from your total area.

Step 4: Account for Soffit and Fascia

If you’re replacing soffit and fascia, measure the length and width of soffit areas and the length of fascia boards.

Siding Squares Explained

In the siding industry, a “square” equals 100 square feet of coverage. When ordering siding, materials are typically sold in squares rather than individual square feet. Our calculator converts your total area into siding squares and rounds up to ensure you have enough material.

Common Mistakes When Measuring

  • Forgetting to subtract openings: Windows and doors significantly reduce the amount of siding needed.
  • Underestimating waste: Most projects require 10-15% extra material for cuts, mistakes, and future repairs.
  • Ignoring gable areas: Triangular gable ends can account for a substantial portion of your total area.
  • Not accounting for trim: Corner posts, starter strips, and J-channel are essential for proper installation.
  • Measuring only one side: Remember to measure all sides of your home, as they may have different dimensions.

FAQ

How many siding squares do I need for a 30 ft × 10 ft wall?

A 30 ft × 10 ft wall has an area of 300 square feet, which equals 3 siding squares (300 ÷ 100 = 3). With a 10% waste allowance, you would need approximately 3.3 squares, which rounds up to 4 squares for ordering.

What’s the difference between siding squares and square feet?

Siding squares are an industry measurement where 1 square equals 100 square feet. Contractors typically order siding in squares rather than calculating individual square feet.

How much extra siding should I order for waste?

Most professionals recommend ordering 10-15% extra material to account for cuts, mistakes, and pattern matching. Complex designs with many corners and angles may require even more waste allowance.

Can I use this calculator for different siding materials?

Yes, our calculator works for vinyl, wood, fiber cement, and engineered wood siding. Each material has different coverage factors that are automatically applied in the calculations.

How do I calculate linear feet for wood siding?

For wood siding, linear feet = adjusted area × linear feet factor. The factor depends on the nominal width of the boards and accounts for the overlap between courses.

What trim pieces do I need for siding installation?

Common trim pieces include outside corner posts, inside corner posts, starter strips, J-channel around windows and doors, and fascia. Our calculator provides estimates for these based on your measurements.

For more construction calculators, check out our Flooring Calculator and Furnace Size Calculator.