Paint & Walls

Insulation Calculator – Batts & Coverage

Estimate the insulated wall area and the number of packages required based on the coverage printed on the product.

Updated: August 30, 2026 · Published by BetterHomeHabits

Quick answer

An 80 ft exterior wall run at 8 ft high equals 640 sq ft before subtracting doors and windows.

Purpose
Estimate insulation area and package count for rectangular walls after subtracting openings.
Formula
Net wall area = wall length × height − openings. Packages = net area × (1 + waste) ÷ package coverage.

How this calculator works

Estimate the insulated wall area and the number of packages required based on the coverage printed on the product.

Formula
Net wall area = wall length × height − openings. Packages = net area × (1 + waste) ÷ package coverage.

Example

An 80 ft exterior wall run at 8 ft high equals 640 sq ft before subtracting doors and windows.

How to get a better estimate

  • R-value requirements vary by climate zone and assembly.
  • Use the package coverage for the exact batt width and thickness.
  • Do not compress insulation to force it into a cavity.

What the result means

The result is a planning estimate. Dimensions, coverage, density, packaging and installation conditions vary by product and project. For purchasing, compare the result with the exact product label or supplier specification. For structural, electrical, code-regulated or safety-critical work, use an appropriately qualified professional.

Common questions about the Insulation Calculator

What does this calculator estimate?

Estimate the insulated wall area and the number of packages required based on the coverage printed on the product.

What formula does it use?

Net wall area = wall length × height − openings. Packages = net area × (1 + waste) ÷ package coverage.

How should I use the result?

Use it as a planning estimate, then verify the dimensions and replace editable defaults with the specifications for the product or service you actually intend to buy.

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