Insulation R-Value Calculator

Not sure if your wall insulation meets code for your climate zone? This calculator instantly converts between R-value and thickness for 9 common materials — and shows you IECC minimum requirements so you pass inspection the first time. Select an insulation material, enter thickness to get R-value, or enter target R-value to find required thickness. Built-in IECC climate zone reference shows minimum R-values for walls, ceilings, and floors at a glance. WHAT IT CALCULATES: R-Value from Thickness: - Select an insulation material from the built-in list - Enter the installed thickness in inches - Get the total R-value and U-factor instantly Required Thickness: - Choose your insulation material - Enter your target R-value - See the exact thickness needed to meet that R-value MATERIALS INCLUDED: - Fiberglass Batt (R-3.2/in) - Fiberglass Blown (R-2.5/in) - Cellulose Blown (R-3.5/in) - Mineral Wool (R-3.3/in) - XPS Foam Board (R-5.0/in) - EPS Foam Board (R-3.8/in) - Polyisocyanurate (R-6.0/in) - Spray Foam Open Cell (R-3.6/in) - Spray Foam Closed Cell (R-6.5/in) IECC CLIMATE ZONE REFERENCE: - Built-in IECC climate zone lookup (Zones 1 through 7-8) - See minimum R-value requirements for walls, ceilings, and floors - Quickly check if your insulation meets code for your zone KEY FEATURES: - Two-way calculator: R-value from thickness or thickness from R-value - U-factor output for energy calculations - 9 common insulation materials with accurate R-per-inch values - IECC climate zone minimum requirements built in - Works completely offline - No account or login required BUILT FOR THE JOB SITE: Whether you are an insulation contractor, general contractor, home inspector, or energy auditor, InsulR Calc gives you quick R-value lookups and thickness calculations. Enter your material and thickness to get R-value, or enter your target R-value to find required thickness in seconds. Supports all common residential and commercial insulation materials per IECC and ASHRAE standards.