How many packages of insulation do I need for 480 sq ft?
For the worked example (480 sq ft with a product that covers 67.81 sq ft per package) the material list is Insulation: 8 packages (calculated 7.08 packages, based on 67.81 sq ft per package (the value you entered)). Quantities to buy are whole units rounded up from the calculated amounts. Enter your own measurements in the calculator above for your exact list.
How to use this calculator
- Choose wall, attic / floor or a known area, and enter the dimensions.
- For several identical areas, set the number of identical areas.
- Enter the coverage per package printed on the insulation you chose.
- Copy, print or share the material list.
How this is calculated
- Wall area = length × height − openings
- Attic / floor area = length × width
- Total area = area × number of identical areas (× (1 + allowance ÷ 100) if you add one)
- Packages = round up (total area ÷ coverage per package)
Geometry is deterministic. Material coverage, density, installation waste and product yield can vary. We expose those assumptions so you can replace them with the values printed on the products you are actually buying. Treat every result as an estimate. Items on your list are labelled Calculated (straight from your measurements) or Estimated (depends on an assumption), and “Buy” quantities are whole units rounded up.
Sources
No third-party figure is built into this calculator. Quantities come from geometry and from the values you can see and edit under “Assumptions” below, each labelled by where it comes from.
Last reviewed: . See the methodology.
Assumptions
These starting values are used until you change them. They are typical, not universal. Check the label on the product you are buying.
| Assumption | Starting value | Where it comes from |
|---|---|---|
| Packages | Whole packages, rounded up | Mathematical – Area ÷ coverage per package, never rounded down |
| Extra allowance | 0% | Common planning default |
| Coverage per package (optional) | You enter it | You enter it (product / supplier) |
Worked example
480 sq ft to cover, with a product printed as 67.81 sq ft per package:
- Insulation: 8 packages (480 sq ft required, 542.5 sq ft supplied) · 67.81 sq ft per package (the value you entered)
Common questions
Does this tell me what R-value I need?
No. Required R-value, facing, vapor-retarder placement, fire assemblies and code compliance depend on your climate, assembly and local requirements. This tool only converts an area into a quantity.
Why is there no default coverage?
Package coverage depends on the product, thickness and R-value. Enter the figure printed on the package you are buying.
Should I round up?
Yes, and the tool does: you cannot buy part of a package, and it never rounds down.
Guides
- How Much Insulation Do I Need?Area to insulate divided by coverage per package, rounded up.
- How to Measure for Insulation: Walls, Floors and AtticsWall, attic and floor areas, openings and identical sections.
- How to Measure a Room for a Material EstimateFloor, wall and ceiling area from a tape measure and a sketch.