Insulation Calculator
Enter the area you're insulating and the coverage per package (printed on the product label) to calculate exactly how many batts or rolls to buy.
Packages needed
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Enter your area to calculate.
How the Insulation formula works
A simple coverage-based calculation:
Packages needed = ceil( Area to cover / Coverage per package )
Step-by-step calculation
- Measure the total area (walls, attic, or floor) you're insulating in square feet.
- Check the coverage area printed on your chosen insulation product's packaging.
- Divide total area by coverage per package and round up to a whole package.
Worked example
An attic with 1,200 ft² to insulate, using batts that cover 88.75 ft² per package: Packages needed = ceil(1,200 / 88.75) = 14 packages.
Frequently asked questions
What R-value do I need?
Recommended R-values vary significantly by climate zone and application (attic, wall, floor) — check your region's building code recommendations or a source like the US Department of Energy's zone map for a specific target.
Should I round up or down on packages?
Always round up — buying a partial package isn't possible, and running short mid-installation means an extra trip and potential seams or gaps in coverage.