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Insulation Batt Calculator

Estimate how many packages of batt insulation you need to cover an area, using your product's stated coverage.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-25 · v1.0.0

Market
Imperial · sales tax
39.37 ft26.25 ft
Schematic, drawn to the proportions you entered — not to scale on screen.
Who is doing the work?

The standard allowance most suppliers and estimating guides assume for ordinary work.

Estimated insulation batt needed

12 packages

High confidence
Area to insulate
1033.34 sq ft
Area with waste factor
1136.67 sq ft

Running these inputs gives 12 packages as the result. Currently reading for United States under IRC 2024 — pick a different market above and the figures re-cast accordingly.

Estimated cost — your price

This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • Batt/roll insulation coverage per package varies by R-value, thickness, and brand — always use the square footage printed on your specific product's packaging for an accurate count

Your workspace

Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.

Still deciding? Batt vs Blown-In Insulation — the factors that actually differ, with no invented prices.

Frequently asked questions

Why isn't there a default coverage number I can just trust?
Batt insulation coverage per package varies a lot by R-value and thickness — an R-13 package covers a different area than an R-38 package of the same physical size. Always use your specific product's printed coverage.
Does higher R-value always mean better insulation?
Higher R-value means more resistance to heat flow, but the right R-value depends on your climate zone and where in the house you're insulating (attic, wall, floor) — check local building code recommendations.
Should I compress batts to fit a smaller space?
No — compressing batt insulation reduces its effective R-value. If a stud bay is shallower than the batt's thickness, use a batt rated for that depth instead.