Insulation Calculator
The Insulation Calculator estimates how many packages of batt or roll insulation you need to cover an area, based on the coverage listed on your specific product.
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How This Tool Works
Enter the area you're insulating and how much area a single package of your chosen insulation covers, to get the number of packages needed.
Formula & Method
Packages needed = (area × (1 + waste%)) ÷ coverage per package (as listed on your specific insulation product).
Example Calculation
A 500 sq ft attic using insulation that covers 40 sq ft per package needs about 13 packages with a 5% waste allowance.
Frequently Asked Questions
How do I find my insulation's coverage rate?+
Check the packaging — it's usually printed as square feet covered per bag or roll, and varies based on R-value and thickness.
What R-value do I need?+
Recommended R-values vary by climate zone and location in the home (attic, walls, floor) — check the U.S. Department of Energy's recommendations for your zip code.
Should I insulate over existing insulation?+
In many cases, yes — adding a layer perpendicular to old insulation can boost R-value, but check for moisture issues first.
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