How this estimate works
The calculator applies: ceil(area x (1 + waste/100) / coverage). Keep measurements in one unit system and round up when suppliers sell whole units.
Limitations
Required R-value, thickness, thermal bridges, vapour control, and local code come first.
Source to check
Read the authoritative guidance for insulation calculator
Frequently asked question
Does more insulation always help? Only when installed to the required thickness with gaps and moisture details addressed.