How much insulation do I need?

Calculate total wall area (perimeter × height) plus ceiling area (length × width). Choose R-value for your climate zone. Divide area by bag coverage (40-100 sq ft per bag depending on type).

What R-value do I need?

Attic: R-38 to R-60 (most climates). Walls: R-13 to R-21. Floors: R-25 to R-30. Basements: R-10 to R-15. Higher R-values = better insulation. Check local building codes for minimums.

How much does insulation cost?

Fiberglass batts: $0.50-1.50/sq ft. Blown-in cellulose: $1.00-2.00/sq ft. Spray foam: $3.00-7.00/sq ft. Rigid foam boards: $1.50-3.00/sq ft. Installation adds $1-3/sq ft.

What type of insulation should I use?

Batts: DIY-friendly for walls between studs. Blown-in: attics, irregular spaces. Spray foam: best R-value, air sealing. Rigid foam: basements, exterior. Choose based on application and budget.

Do I need a vapor barrier?

Yes for walls and crawl spaces in cold climates. No for ceilings in hot climates. Vapor barrier prevents moisture buildup in insulation. Install on warm side of insulation. Check local codes.

Insulation Calculator

Calculate insulation materials and R-value needed

Insulation Calculator

Calculate insulation needed for walls, attics, and basements. Get R-value recommendations, material quantities, and cost estimates.

Room Dimensions

Room Length *

Length of the room

Room Width *

Width of the room

Wall Height *

Height for wall insulation calculation

R-Value Selection

Choose R-Value

R-19: Walls in moderate climates (recommended)

R-Value Recommendations

R-value measures insulation effectiveness. Higher R-values provide better insulation. Recommended R-values: Attics R-38 to R-60, walls R-13 to R-21, floors R-25 to R-30, basements R-10 to R-15. Check local building codes for minimum requirements.

Fiberglass batts come pre-cut to fit between standard 16-inch stud spacing. Each bag typically covers 40-60 square feet depending on R-value and batt thickness. Always wear protective equipment when handling insulation materials.

Frequently Asked Questions

Everything you need to know about this tool