Insulation Calculator
Calculate insulation material and cost for fiberglass batt, blown-in, or spray foam by R-value target.
Total Project Cost
$420.00
Est. Annual Savings
$300.00
Payback Period
1.4 years
Project Details
| Total Area | 400 sq ft |
| Fiberglass Batt (R-19) | 10 rolls |
| Cost per sq ft | $0.55 |
| Material Cost | $220.00 |
| Labor Estimate | $200.00 |
| Total Project Cost | $420.00 |
Energy Savings Estimate
| Estimated Annual Energy Savings | $300.00 |
| Payback Period | 1.4 years |
| 5-Year Net Savings | $1,080.00 |
| 10-Year Net Savings | $2,580.00 |
Use the Insulation Calculator above to calculate your results. Enter your values and see instant results — all calculations run in your browser.
Disclaimer: This calculator is for informational purposes only and does not constitute tax, financial, or legal advice. Results are estimates based on the information you provide and current rates. Always consult a qualified tax professional or financial advisor for advice specific to your situation.
How It Works
Our Insulation Calculator precisely estimates the material and cost for fiberglass batt, blown-in cellulose, or spray foam to meet your desired R-value. In 2026, with energy costs projected to rise by an average of 4.5% annually, optimizing your home's insulation is crucial for significant savings and reduced carbon footprint.
The calculator first determines the required material thickness based on the target R-value and the R-value per inch for the selected insulation type. It then multiplies this thickness by the area to be insulated to find the total volume, which is then converted to units (e.g., square feet of batts, bags of blown-in, or board feet of spray foam) and multiplied by the 2026 average material cost per unit.
Always consider the R-value of existing insulation; you might only need to add to it. A common mistake is underestimating the true square footage, including joists and odd-shaped areas. Remember that labor costs are not included here and can add 30-50% to your total project cost.
Example: Insulating a 1,500 sq ft Attic with Blown-in Cellulose
- 1 Input: Attic Area = 1,500 sq ft, Desired R-value = R-49 (common for 2026 energy codes), Insulation Type = Blown-in Cellulose (R-value per inch = 3.7).
- 2 Calculation: Required thickness = R-49 / 3.7 R/inch = 13.24 inches. Total volume = 1,500 sq ft * 13.24 inches * (1 ft / 12 inches) = 1,655 cubic feet. Assuming 3.5 lbs/cubic foot density, this is 5,792.5 lbs. A 30 lb bag of blown-in cellulose covers approximately 11.5 cubic feet at R-49. So, 1,655 cubic feet / 11.5 cubic feet/bag = 144 bags.
- 3 Intermediate Result: You will need approximately 144 bags of blown-in cellulose.
- 4 Final Result: With the average 2026 cost of blown-in cellulose at $38.50 per 30 lb bag, the estimated material cost for this project is 144 bags * $38.50/bag = $5,544.00. This doesn't include potential equipment rental (around $150/day) or professional installation.
Source: HomeAdvisor · Last updated: April 2026
Frequently Asked Questions
What R-value insulation do I need?
What type of insulation is the most cost-effective?
How much money does insulation save on energy bills?
You might also need
Concrete Calculator
Calculate cubic yards of concrete needed for slabs, columns, and footings. See bags needed and estimated cost.
Paint Calculator
Calculate gallons of paint needed for a room. Accounts for doors, windows, and number of coats.
Flooring Calculator
Calculate flooring material needed and cost for hardwood, laminate, vinyl, tile, or carpet.