What to enter
- Enter wall or building dimensions and choose the appropriate project mode.
- Deduct doors and windows where appropriate.
- Enter the coverage provided by one package of your chosen siding.
- Add waste and optionally enter a package price.
Siding Calculator
Estimate siding coverage, panels and waste allowance.
My ProjectNo saved space selectedSave a room once and reuse it here.
Your estimate
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Ready when you are
Enter wall dimensions, openings and package coverage to estimate siding packages and optional cost.
Recommended purchase
0
Siding packages recommended
Includes your selected waste allowance.
Estimated material cost—
Gross wall area—
Openings deducted—
Net siding area—
Waste allowance—
Area recommended—
Coverage purchased—
Package coverage varies.
The starting coverage shown here is only an editable example. Replace it with the exact coverage printed on the siding product you plan to buy.
Shopping estimate
Related: insulation calculator—
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Plan with confidence
How to use the Siding Calculator
Estimate siding for one wall or a rectangular building perimeter, then round the required coverage into full packages.
How the calculation works
PlanCalq calculates gross wall area, subtracts the opening area and adds a user-selected waste allowance.
The recommended coverage is divided by the package coverage you enter and rounded up to a complete package.
Calculation summary
Gross wall area − openings = net siding areaNet area × (1 + waste %) = recommended coverageRecommended coverage ÷ package coverage = packages required (rounded up)Worked example
Example: siding around a rectangular building
- Building: 8 m × 10 m
- Wall height: 2.7 m
- Openings: 15 m²
- Waste: 10%
- Package coverage: 2 m²
Planning resultGross wall area is 97.2 m²; after openings and waste the planning coverage is about 90.4 m², which rounds to 46 two-square-metre packages.
Siding is estimated from exterior wall area rather than floor area. Significant openings are deducted, then a waste allowance is added before the result is rounded to full packages.
How to read the result
- Use package count for ordering and net wall area for comparing material systems.
- Small openings are sometimes left undeducted as a conservative allowance; large openings should normally be measured.
- Accessory quantities such as corners and starter pieces should be taken from the chosen siding system.
What this calculator does not cover
- Gables, bump-outs, dormers and non-rectangular walls need separate area measurements.
- The tool does not design weather barriers, drainage planes, flashing or fastening systems.
- Local wind, fire and building requirements can affect product selection and installation.
GuideRenovation budget planning
Build a practical renovation budget by separating scope, material quantities, purchase units, labour, contingency and project-specific costs.
GuideRenovation contingency allowanceUnderstand the difference between material waste and renovation contingency, what creates uncertainty, and how to build a realistic allowance into a project budget.
GuideInterpreting calculator estimatesLearn the difference between theoretical quantity, recommended quantity, purchase quantity and estimated cost so you can use calculator results responsibly.
Common questions
Siding Calculator FAQs
Should I subtract windows and doors?
Yes for significant openings. Small openings may be left in when you prefer a slightly more conservative quantity.
Does this include trim pieces?
No. Corners, starter strips, channels, flashing and other accessories depend on the siding system and project details.
Why is waste necessary?
Cuts around corners and openings, damaged pieces and minimum reusable offcut lengths create unavoidable material loss.