Roof Insulation Calculator

R-Value, Square Footage & Cost Estimator

The Roof Insulation Calculator returns the bag count, board count, or cubic feet of insulation needed to bring your attic up to the recommended R-value for your climate zone. Cold zones need R-49 to R-60 in the attic; warm zones can use R-30 to R-38. Select your zone, attic square footage, and insulation type (fiberglass batt, blown cellulose, blown fiberglass, spray foam) and the tool returns quantity and cost. Combine with our Insulation Guide and Vents Calculator.