Calculated result
7packages
Batts or rolls to order
Formula
EXT-INSUL-001240 ft²
Net coverage area
264 ft²
Area including waste
Exterior calculator
Insulation calculator
Batt or roll count from net coverage area, product coverage and a visible cutting allowance.
Reviewed formula · v1.0.0
Project inputs
Enter field measurements. Unit conversion happens before the reviewed formula is applied.
All values can be refined when you edit the estimate. This tool does not replace field verification or local requirements.
Transparent cost view
Use visible planning values, then replace them with actual job costs before quoting.
Material cost$595
Direct cost$985
Overhead + contingency$99
Markup + tax$130
Estimated project total$1,214
How this calculator works
A transparent insulation calculator takeoff.
This calculator divides a rectangular coverage area by the selected batt or roll coverage and rounds to whole packages after a visible cutting allowance.
Worked example. Example: a 20 ft × 12 ft attic is 240 ft². With 10% waste and 40 ft² batts, the purchase quantity rounds to 7 batts or rolls.
- 1. Measure the actual cavity or attic area, not the building footprint alone.
- 2. Enter net coverage from the selected insulation package.
- 3. Increase allowance around openings, wiring and irregular bays.
Need the broader workflow? Read the exterior planning guide.
Questions
Common questions about this insulation calculator.
Does this select an R-value?
No. Product R-value, cavity depth and climate requirements must be confirmed independently.
Can I use this for blown-in insulation?
Only if you enter the bag or bag-coverage stated by that product. This tool does not convert R-value into blown depth.