Rex says
Everyday utility math — the kind you'd otherwise pull up four browser tabs for. I keep it to one clean answer.
Try a scenario
Click to load — tweak from there.Inputs
Cuts, breakage, and mistakes. 10% is standard.
Result
Siding squares
24.6
Material cost
$6,372
Net wall area (sq ft)
2,228
Cost per sq ft
$2.86
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter building perimeter (ft).
- 2Enter wall height (ft).
- 3Enter window and door area (sq ft).
- 4Enter siding per square ($).
- 5Enter waste allowance (%) — Cuts, breakage, and mistakes. 10% is standard..
- 6Read your siding squares on the right — it updates as you type.
- 7Hit Share to keep the scenario or send it to someone.
About this calculator
Siding is also sold by the square. Subtract window and door openings, but keep the waste allowance high — corners and trim eat material fast.
Worked example
Using the values the calculator loads with:
Inputs
- Building perimeter: 136 ft
- Wall height: 18 ft
- Window and door area: 220 sq ft
- Siding per square: 260 $
- Waste allowance: 10 %
Results
- Siding squares: 24.6
- Material cost: $6,372.08
- Net wall area (sq ft): 2,228
- Cost per sq ft: $2.86
What each field means
Inputs
- Building perimeter (ft)
- The building perimeter used in the calculation, measured in ft. Starts at 136 ft so you have a working example on load.
- Wall height (ft)
- The wall height used in the calculation, measured in ft. Starts at 18 ft so you have a working example on load.
- Window and door area (sq ft)
- The window and door area used in the calculation, measured in sq ft. Starts at 220 sq ft so you have a working example on load.
- Siding per square ($)
- The siding per square used in the calculation, measured in $. Starts at 260 $ so you have a working example on load.
- Waste allowance (%)
- Cuts, breakage, and mistakes. 10% is standard.
Results
- Siding squares
- Returned as a decimal number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Material cost
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Net wall area (sq ft)
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Cost per sq ft
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the siding calculator work?
Siding is also sold by the square. Subtract window and door openings, but keep the waste allowance high — corners and trim eat material fast. The underlying maths is: Net wall area = Perimeter × Height − openings. Squares = Area ÷ 100, plus waste.
What do I need to enter?
5 values: building perimeter, wall height, window and door area, siding per square, and waste allowance. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the siding squares result mean?
It is returned as a decimal number and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Estimates assume standard, average conditions — local rules, pricing, and materials vary.
Who is this tool for?
It's built for anyone doing everyday planning maths — a quick estimate that would otherwise need four browser tabs and a calculator app.
Accuracy and limitations
- Estimates assume standard, average conditions — local rules, pricing, and materials vary.
- Results are rounded for readability; add a buffer before ordering, booking, or committing.
- Double-check anything with a real cost attached against a local quote.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Siding Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/siding
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/siding" target="_blank" rel="noopener">Siding Calculator — RevenueLab</a> (2026).</p>
Source: [Siding Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/siding) (2026).