FREE DIY ESTIMATOR
Insulation Calculator
Estimate net wall area, insulation pack count, waste allowance, and primary material cost for a rectangular room.
How the insulation estimate works
The calculator finds total wall area from room perimeter and wall height, subtracts doors and windows, adds your selected waste allowance, then divides by the square-foot coverage per insulation pack.
Use the package coverage
Insulation products vary by width, thickness, R-value, batt length, and package quantity. Use the actual square-foot coverage printed on the product you plan to buy.
What the calculator does not choose for you
It does not determine the correct R-value, insulation type, vapor-control strategy, or cavity depth. Those choices depend on climate, wall assembly, local requirements, and the specific project.
Plan the installation
Read the insulation planning guide or use the Project Planner to build the rest of your material list.