What to enter
- Choose a room, single wall or ceiling and enter the dimensions.
- Deduct doors and windows where applicable.
- Enter the coverage supplied by one insulation package.
- Choose waste and optionally enter the package price.
Insulation Calculator
Estimate insulation area, packs and project quantities.
My ProjectNo saved space selectedSave a room once and reuse it here.
Your estimate
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Ready when you are
Estimate insulation coverage, waste, packages to buy and optional material cost.
Recommended purchase
0
Packages recommended
Includes your selected waste allowance.
Estimated material cost—
Net insulation area—
Waste allowance—
Coverage recommended—
Coverage per package—
Coverage purchased—
Selected product ratingNot specified
PlanCalq intentionally does not recommend an R-value.
Required thermal resistance depends on climate, assembly type, local code and the exact product. Use this tool after you have selected an appropriate insulation specification.
Shopping estimate
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Plan with confidence
How to use the Insulation Calculator
Estimate how many insulation packages are needed to cover walls or a ceiling using the coverage printed on the product package.
How the calculation works
PlanCalq calculates the net surface area, adds your selected waste allowance and divides the result by the coverage of one insulation package.
The quantity is rounded up to full packages. Any R-value field is informational only; PlanCalq does not decide the insulation performance required for your building.
Calculation summary
Gross area − openings = net insulation areaNet area × (1 + waste %) = recommended coverageRecommended coverage ÷ package coverage = packages to buy (rounded up)Worked example
Example: insulation for one 4 m wall
- Wall: 4 m × 2.7 m
- Openings: 2 m²
- Waste: 5%
- Package coverage: 5 m²
Planning resultThe net area is 8.8 m²; with waste it becomes 9.24 m², so two 5 m² packages are required.
The quantity calculation is intentionally separate from thermal design. PlanCalq determines how much coverage to buy once you have already chosen the correct insulation product and performance level.
How to read the result
- Use the package count only after confirming that the insulation type, thickness and thermal performance suit the assembly.
- Coverage printed on the package is the best purchase input because the same product family may be sold in several thicknesses and pack sizes.
- If cavities have unusual spacing or many obstructions, consider additional cutting waste.
What this calculator does not cover
- PlanCalq does not select a required R-value or U-value for your location.
- Moisture control, vapour management, fire performance and ventilation are separate design considerations.
- Local energy codes and assembly requirements should be checked before purchasing material.
GuideRenovation budget planning
Build a practical renovation budget by separating scope, material quantities, purchase units, labour, contingency and project-specific costs.
GuideInterpreting calculator estimatesLearn the difference between theoretical quantity, recommended quantity, purchase quantity and estimated cost so you can use calculator results responsibly.
Common questions
Insulation Calculator FAQs
Does PlanCalq tell me what R-value I need?
No. The correct R-value depends on location, building assembly and applicable standards or codes.
Should I subtract windows and doors?
Yes when estimating wall insulation, especially where openings represent a meaningful share of the wall area.
Why use package coverage instead of batt dimensions?
Package coverage is the simplest product-specific input and already accounts for how much material is contained in the package you will actually purchase.