Overview
What Is an Insulation Calculator?
This tool calculates the total R-value (thermal resistance) provided by combining multiple insulation layers, and the area of insulation needed.
Calculate insulation R-value needed.
This tool calculates the total R-value (thermal resistance) provided by combining multiple insulation layers, and the area of insulation needed.
Useful for planning attic, wall, or floor insulation to meet recommended R-value targets.
Input square footage of the space.
Input the specific product's R-value rating.
Input how many inches thick you'll install.
The result updates automatically.
A measure of thermal resistance - higher R-value means better insulating performance.
This varies significantly by climate zone and location (attic, walls, floor) - check your local building code or energy authority recommendations.
Multiply the R-value per inch by the thickness in inches for a single material layer.
Yes, R-values of different layers add together for combined total resistance.
Yes, materials like spray foam, fiberglass, and cellulose have different R-values per inch of thickness.
No, calculations happen entirely in your browser.
Generally more insulation improves energy efficiency, though there are diminishing returns and cost considerations at very high levels.
Yes, colder climates typically require higher R-values for adequate insulation performance.
For significant projects, a professional energy audit or contractor consultation can help determine optimal insulation strategy.
Yes, completely free with no sign-up required.