Insulation Calculator
Calculate how much insulation you need for walls or ceilings.
Enter area and R-value to get batts, rolls, or blown-in estimates.
Insulation Needed
Insulation calculation depends on the type and R-value selected.
Unit conversions:
1 sq ft = 0.0929 sq m1 inch = 2.54 cm
Common R-values and thickness (imperial):
| R-Value | Fiberglass Batt | Blown-In Fiberglass | Blown-In Cellulose |
|---|---|---|---|
| R-13 | 3.5 in | 5.3 in | 3.7 in |
| R-19 | 6.25 in | 7.7 in | 5.4 in |
| R-30 | 9.5 in | 12.2 in | 8.5 in |
| R-38 | 12 in | 15.4 in | 10.8 in |
Common R-values and thickness (metric):
| R-Value | Fiberglass Batt | Blown-In |
|---|---|---|
| R-2.0 | 90 mm | 95 mm |
| R-3.5 | 160 mm | 165 mm |
| R-5.0 | 220 mm | 230 mm |
Fiberglass batts: standard roll covers ~40 sq ft (3.7 sq m) for R-13, ~75 sq ft (7 sq m) for R-19.
Blown-in: typically sold in bags covering ~40 sq ft (3.7 sq m) at R-30.