Insulation R-Value Calculator
Calculate total R-value from multiple layers. Free, instant.
How to Use Insulation R-Value Calculator
1
Enter R-value for each layer.
2
Get total R-value.
3
Copy or download your result.
Frequently Asked Questions
What R-value do I need?
Attic: R-38 to R-60. Walls: R-13 to R-21. Floor: R-25 to R-30.