Interior & Finishes

Insulation Calculator

This insulation calculator turns area and target R-value into packages or bags; our insulation installation guide covers R-values by climate zone. Insulation packaging lists how many square feet each bundle or bag covers at a given R-value — and for blown-in insulation that coverage changes with the R-value you target. Enter the area and the coverage from the package chart for your target R-value to get the number of packages, plus an installed cost range by insulation type.

The R-value you need depends on your climate zone and your state's energy code. New York spans IECC climate zones 4A–6A; the U.S. Department of Energy publishes recommended levels for existing homes.

Results from this insulation calculator are planning estimates; confirm quantities and prices with your supplier or contractor before you order.

Your results will appear here

Enter your measurements and press Calculate. Defaults show a typical example.

How to use the insulation calculator

Measure the area — attic floor area, or the wall area to fill.
Choose the insulation type.
Look up your target R-value for your climate zone and code.
Enter the coverage per package that the product chart lists for that R-value.

Formula

Packages = area × (1 + waste) ÷ coverage per package at the target R-value. Installed cost = area × cost per sq ft (typical 2026 pricing: batts $0.30–$2.10, blown-in $0.50–$2.30, spray foam $1–$4.50 per sq ft).

Worked example

1,000 sq ft of attic with a blown-in bag that covers 40 sq ft at your target R-value: 1,050 ÷ 40 = 27 bags; installed cost about $500–$2,300 at typical national pricing.

Tips for using the insulation calculator

Use the coverage chart on the package; blown-in coverage changes with the R-value you target.
Seal air leaks before adding insulation for the biggest comfort gain.
Keep insulation away from recessed lights and flues unless they are rated for contact.