Insulation Calculator
Batts or rolls needed by R-value.
Enter your values
Results update instantly as you type — no submit needed.
Results
- Bags or rolls needed
- 20
- Area with 5% waste
- 945 sq ft
- Target R-value
- R-38
- Estimated cost
- $840.00
- Cost per square foot
- $0.93
Quick answer
Insulation is sized by area and R-value; higher R means more thickness and better heat resistance.
How to use the Insulation Calculator
- 1Measure the area to be insulated.
- 2Check coverage per bag on the label.
- 3Pick the R-value recommended for your climate zone.
Frequently asked questions
What R-value do attics need?
R-38 to R-60 depending on climate zone.
Can I add over old insulation?
Yes, as long as the new layer is unfaced.