Insulation Calculator

Calculate insulation packages from measured area, label coverage and waste, with a target R-value reminder and a rounded package example. Calculate it clearly with Figur.

Divide waste-adjusted area by labeled package coverage

Order area = area in square feet × (1 + waste ÷ 100). Packages = order area ÷ coverage per package, rounded up to whole rolls or bags. Enter the coverage printed for the exact product and target R-value. R-value is shown as a buying reminder only: changing it does not recalculate coverage, thickness or package count.

Method and assumptions

Order area = area × (1 + waste ÷ 100). Packages = round up(order area ÷ coverage). Target R-value is displayed but is not part of the package formula.

  • Area is the measured net area to insulate; openings and separate surfaces are not measured or deducted automatically.
  • Coverage is user-entered square feet per package at the intended R-value. There is no built-in roll size or bag yield.
  • R-value does not select a product, derive installation depth or verify thermal performance. Update coverage yourself when changing R-value.
  • Only entered waste and whole-package rounding are included. Air sealing, vapor control, ventilation, labor and code compliance are excluded.

Planning takeoff, not a binding bid, structural design or engineering advice. Confirm field measurements, product coverage, installation requirements and supplier quantities before buying.

Sources and references

The result uses your inputs and the tool's documented assumptions; it does not fetch current prices, rates or products.

Worked example

Insulate 1,000 sq ft at target R-38 with label coverage of 40 sq ft per package and 5% waste.

1,000 × 1.05 = 1,050 sq ft to cover; 1,050 ÷ 40 = 26.25, rounded up to 27 packages. R-38 is a label reminder, not a coverage calculation.

Frequently asked questions

Will changing R-value change the package count?

No. It changes the displayed target only. Enter the matching label coverage yourself; the same area, waste and coverage give the same count.

Can I use this for rolls or blown-in bags?

Yes, as an area-based package estimate if you enter the correct coverage at the intended installed R-value. It does not calculate blown-in depth or density.

Does it subtract windows and doors?

No. Measure the net area before entering it. Different products or R-values should be estimated separately.

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