Calculate the number of bags of blown-in insulation needed for your attic or enclosed walls. Enter the area, desired R-value, and insulation type (fiberglass or cellulose) for accurate bag counts and coverage estimates.
Enter Your Measurements
Results
Bags Needed (with 10% extra)
47
bags
Bags (exact)
42
bags
Insulation Depth
8.0
inches
R-Value to Add
28
Volume Needed
667
cubic feet
Formula
How to Use This Calculator
How to Use
- 1
Measure the attic floor area in square feet.
- 2
Enter the desired total R-value (R-38 to R-60 is recommended for most attics).
- 3
Enter the existing R-value if adding to existing insulation (0 if starting fresh).
- 4
Select the material type: fiberglass (R-2.5/inch) or cellulose (R-3.5/inch).
Frequently Asked Questions
Frequently Asked Questions
Is blown-in insulation better than batts?
How deep should blown-in attic insulation be?
In-Depth Guides
Related Calculators
Related Calculators
About This Calculator
This calculator uses the formula: Depth = (Target R-Value - Existing R-Value) ÷ R per inch | Bags = (Area ÷ Coverage per Bag) × (Depth ÷ 6) × 1.1. All calculations follow industry-standard methods. Results are estimates — always verify with a licensed professional for structural or code-compliant work.
Built and maintained by the CalcSmart team. Last updated March 2026.
▶Embed this calculator on your website
Copy and paste this code into your page:
<iframe src="https://calcsmart.io/embed/blown-in-insulation-calculator" width="100%" height="520" frameborder="0" style="border-radius:8px;border:1px solid #e5e7eb" title="Blown-In Insulation Calculator"></iframe>Free to embed. Attribution link included automatically.