How do I include gable ends?

Calculate the triangular gable area separately (½ × base × height) and add it to the wall area before subtracting openings.

What waste percentage should I use?

8–12% is common. Increase it for complex facades, tall walls, or diagonal installations.

Does this include trim and accessories?

No. Order trim, starter strips, J-channel, and soffit/fascia separately per your product’s coverage.

How many boxes are in a square?

It varies by product. Check your siding’s coverage per box and divide the required squares accordingly.

Can I enter multiple walls at once?

Run each wall separately and add the squares together for the full project.

construction calculator

Siding Calculator

Estimate siding square footage and squares after openings and waste.

Results

Gross area (sq ft): 400.00
Net area (sq ft): 350.00
Area with waste (sq ft): 385.00
Squares (100 sq ft): 3.85

How to use this calculator

Enter wall length and height in feet.
Subtract windows, doors, and other openings.
Add a waste allowance for cuts and pattern staggering.
Review net area, adjusted area, and siding squares to order.

Inputs explained

Wall length/height: Overall wall dimensions for the section you’re covering.
Window area: Total square footage of windows to subtract.
Door/other openings: Any additional openings to exclude from coverage.
Waste allowance: Extra percentage for cuts, laps, and installation errors.

How it works

Net area subtracts window/door openings from gross wall area.

Waste factor adds a buffer for cuts and mistakes.

Squares = area ÷ 100 for standard siding coverage.

Formula

Net = (L × H) − openings
Adjusted = Net × (1 + waste)
Squares = Adjusted ÷ 100

When to use it

Estimating vinyl, fiber cement, or wood siding orders in squares.
Budgeting material before requesting supplier quotes.
Comparing waste assumptions for complex patterns or tall walls.

Tips & cautions

Break the project into multiple wall sections and sum the results for whole-house estimates.
Increase waste for complex facades, diagonal installations, or heavy pattern matching.
Check manufacturer coverage per box/square—exposures and laps change actual coverage.
Does not include trim, soffit, fascia, or starter strips—estimate those separately.
Assumes rectangular walls; gables need triangular area calculations added in.
Exposure and lap differences between products can change real coverage; verify with product specs.

Worked examples

40×10 ft wall, 50 sq ft openings, 10% waste

Net = 350 sq ft
Adjusted = 385
Squares ≈ 3.85

30×9 ft wall, 30 sq ft openings, 8% waste

Net = 240 sq ft
Adjusted ≈ 259
Squares ≈ 2.59

Deep dive

This siding calculator converts wall measurements into net area and siding squares after subtracting openings and adding waste. Enter length, height, windows, doors, and waste to see how many squares to order.

Use it for vinyl, fiber cement, or wood siding takeoffs. Break multi-wall projects into sections, increase waste for complex cuts, and verify coverage per box based on your chosen exposure.

FAQs

How do I include gable ends?: Calculate the triangular gable area separately (½ × base × height) and add it to the wall area before subtracting openings.
What waste percentage should I use?: 8–12% is common. Increase it for complex facades, tall walls, or diagonal installations.
Does this include trim and accessories?: No. Order trim, starter strips, J-channel, and soffit/fascia separately per your product’s coverage.
How many boxes are in a square?: It varies by product. Check your siding’s coverage per box and divide the required squares accordingly.
Can I enter multiple walls at once?: Run each wall separately and add the squares together for the full project.

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