Insulation Batt Pack Calculator
Estimate insulation batts and whole packs from net ceiling, wall or floor area, batt dimensions, pack quantity and allowance.
Your results
Calculation breakdown
- Packs
- ceil(ceil(net m² × allowance ÷ batt m²) ÷ batts per pack)
Worked example
A 90 m² net ceiling using 1,160 × 430 mm batts needs 190 batts after 5% allowance, or 14 packs containing 14 batts each.
Assumptions
- Batt dimensions are installed face dimensions.
- Required thermal rating and clearances are confirmed separately.
Sources
Rates effective 23 August 2026.
How this calculator works
Batt face size determines nominal coverage, but framing, penetrations and edge trimming create offcuts. This tool removes user-entered excluded areas, applies a cutting allowance and respects both whole-batt and whole-pack purchasing, without selecting the required R-value or installation clearances.
Frequently asked questions
Does this calculate the required R-value?
No. Confirm the system R-value and climate-specific compliance requirements with current NCC information and qualified project advice.
Can insulation cover recessed lights?
Only where the fitting and installation are specifically rated and detailed for it; follow the manufacturer and licensed electrician's requirements.
Why enter excluded ceiling area?
Large voids may be excluded, but small penetrations often create extra cutting rather than a useful material saving, so measure conservatively.