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Insulation
Calculator

Estimate insulation costs, rolls or bags needed, and annual energy savings for fiberglass, cellulose, spray foam, and mineral wool insulation projects.

100% FreeInstant ResultsEnergy Savings
Area to Insulate
sqft
100 sqft5,000 sqft
Insulation Type
Target R-Value
R-30
R-11R-60
Current R-Value (Existing Insulation)
None (R-0)
R-0 (None)R-30

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How It Works

Get your insulation estimate in three simple steps.

Enter Your Area

Use the slider to set the total square footage you need to insulate — walls, attic, or crawl space.

Choose Type & R-Value

Select your insulation type and set your target R-value. Optionally enter your current R-value for upgrade estimates.

Get Your Estimate

Instantly see total cost range, packages needed, estimated energy savings, and payback period for your project.

Insulation Type Comparison (2026)

Compare cost, R-value range, and best use for the most popular insulation materials — from rolled insulation and blow in insulation to spray foam insulation.

TypeCost/sqftR-Value Range
Fiberglass Batt$0.50 - $1.50R-13 to R-38
Blown-in Fiberglass$1.00 - $2.50R-11 to R-60
Blown-in Cellulose$0.80 - $2.00R-11 to R-60
Spray Foam (Open Cell)$1.00 - $2.00R-11 to R-45
Spray Foam (Closed Cell)$1.50 - $3.50R-11 to R-50
Mineral Wool (Rockwool)$1.00 - $2.50R-15 to R-45

Prices include material and professional installation. Actual costs vary by location, project size, and contractor. Spray foam insulation calculator cost estimates reflect board-foot pricing converted to sqft at typical thickness.

R-Value Guide by Location

The Department of Energy recommends different R-values based on climate zone and where in your home you are insulating. Use this wall insulation calculator guide alongside the insulation price calculator above to plan your project.

Attic / Ceiling

R-30 to R-60 recommended. Uninsulated attics are the top priority — heat rises, so attic insulation delivers the biggest energy savings. Use our blow in insulation calculator for attic projects.

Exterior Walls

R-13 to R-21 for 2x4 framing, R-19 to R-21 for 2x6 framing. Fiberglass batt and mineral wool are popular choices. Closed-cell spray foam adds structural rigidity.

Floors / Crawl Spaces

R-19 to R-25 recommended. Insulation cellulose or fiberglass batts installed between floor joists help prevent cold floors and moisture problems in unconditioned crawl spaces.

Basement Walls

R-10 to R-19 recommended. Rigid foam or closed-cell spray foam works best against moisture. Proper insulation here prevents up to 30% of a home's total heat loss.

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Frequently Asked Questions

Common questions about insulation cost, materials, and energy savings answered by our free insulation calculator for walls, attics, and more.

Measure the total square footage of the area you want to insulate (length times width for each wall or ceiling section). Enter that area into the calculator along with your desired R-value and insulation type. The calculator returns how many rolls or bags you need plus estimated material and installation cost.
The recommended R-value depends on your climate zone. For most U.S. homes: exterior walls need R-13 to R-21, attic floors need R-38 to R-60, and crawl spaces need R-19 to R-25. Colder climates (zones 5-8) benefit from higher R-values. Check the DOE climate zone map for your specific recommendation.
Fiberglass batt insulation is the most affordable option at $0.50-$1.50 per square foot, making it ideal for DIY wall and attic projects. Blown-in cellulose offers the best value for attic retrofits at $0.80-$2.00 per square foot. Closed-cell spray foam is the most expensive but provides the highest R-value per inch and doubles as a vapor barrier.
Open-cell spray foam costs $1.00-$2.00 per square foot installed, while closed-cell spray foam costs $1.50-$3.50 per square foot. Closed-cell delivers roughly R-6 per inch versus R-3.7 per inch for open-cell, so you need less thickness to reach the same R-value. For a 1,000 sqft attic, expect to pay $1,000-$3,500 total.
Yes, you can layer new insulation over existing insulation to increase R-value. This is common in attics where blown-in cellulose or fiberglass is added on top of existing batts. Enter your current R-value in the calculator to see how much additional insulation you need and the estimated energy savings from the upgrade.
Energy savings depend on your current insulation level, climate, and heating/cooling costs. Upgrading from no insulation (R-0) to R-30 can reduce heating and cooling costs by up to 40-50%. Our calculator estimates annual savings based on the R-value difference and an average $1,200/year energy baseline. Most insulation projects pay for themselves within 3-7 years.
The number of bags depends on the coverage area and target R-value. At R-30, blown-in cellulose covers about 40 sqft per bag and blown-in fiberglass covers about 28 sqft per bag. For a 1,000 sqft attic at R-30, you would need approximately 25 bags of cellulose or 36 bags of fiberglass. Our calculator computes this automatically for any area and R-value.
Absolutely. Older homes often have little or no insulation, making them prime candidates for energy upgrades. Adding insulation to an uninsulated attic typically delivers the highest return on investment of any home improvement. Combined with air sealing, proper insulation can reduce energy bills by 20-50% and significantly improve comfort year-round.

Planning a bigger home project?

Use our Home Addition Cost Calculator to estimate bedroom, bathroom, kitchen, and second-story expansion budgets including insulation requirements.

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