Free tool: Division 07 thermal protection
Insulation estimator: bags, boards, foam and cost per SF
Work out bags of batts or blown-in, rigid boards, or spray foam board feet and sets from the coverage on your product. Add your own prices to see insulation cost per square foot.
Fixed price in 2 business hours. Pay only after you accept.
- Fixed price agreed before any work starts
- Plan review is free
- You pay only after you accept the price and delivery date
- Single-trade estimates in 48 hours
Quick answer
The Bidmere insulation estimator turns an area into bags of batts or blown-in, rigid boards, or spray foam board feet and sets, using the coverage from your product’s label or data sheet. Enter your material and labor costs to get a total and your insulation cost per square foot. It is free and runs in your browser.
Division 07: Thermal protection
Insulation calculator
Bags, boards or spray foam sets from the area and your product’s coverage, with installed R-value and cost per square foot at your prices.
Results
Bidding a commercial job? Send the plans and get a measured takeoff
Get a fixed quote Fixed price in 2 business hours. Plan review is free. Pay only after you accept.Need the whole job measured? This calculator covers one area at a time. Send the plans and we return the full takeoff and estimate. Fixed quote within 2 business hours. Plan review is free, and you pay only after you accept.
Get a fixed quoteHow to use the insulation estimator
Pick the insulation type, enter the area, then enter the coverage from the product you are pricing. Results update as you type.
- Insulation type. Batts or rolls, blown-in or loose-fill, rigid board, or spray foam.
- Area. The square feet of one assembly. Run walls, roofs and under-slab separately.
- Waste. For cut-up framing, trim loss and overspray. The default is 5%.
- Product coverage. Square feet per bag from the batt label, the row for your R-value on the blown-in coverage chart, board size and thickness, or foam thickness and yield per set.
- R-value per inch. Optional for board and foam. Add a target R to see the thickness needed.
- Your unit costs. Material per bag, board or set, install labor per square foot and a lump sum.
The tool does not guess coverage for you. Product coverage changes by manufacturer, R-value and density, so the label is the source.
How the insulation calculator works
Units to order equal the area plus waste, divided by the coverage of one unit, rounded up. Board and foam also report board feet.
| Type | Formula |
|---|---|
| Batts or rolls | Area x (1 + waste %) / SF per bag |
| Blown-in | Area x (1 + waste %) / SF per bag at the target R-value |
| Rigid board | Area x layers x (1 + waste %) / (board width x length) |
| Board feet | Area x thickness (in) x layers |
| Spray foam sets | Area x thickness (in) x (1 + waste %) / yield per set (BF) |
| Installed R-value | Thickness (in) x R per inch |
| Thickness for target R | Target R / R per inch |
| Cost per SF | Total cost / area insulated |
One board foot is 1 SF at 1 in thick, so spray foam and rigid board are often priced by the board foot. The default batt coverage is 106.56 SF per bag, from one R-13, 15 in x 93 in kraft-faced product listing. Other products and sizes differ, so replace it with your label.
Fictional example: one wall area, three ways
Fictional example. An insulation contractor is comparing three options for 2,000 SF of exterior wall.
- Batts: 2,000 x 1.05 / 106.56 SF per bag = 19.7, so order 20 bags.
- Rigid board: 2,000 x 1.05 / 32 SF per 4 x 8 board = 65.6, so order 66 boards. At 2 in thick that is 4,000 board feet. At a fictional R-5 per inch, installed R is 10.
- Spray foam: 2,000 SF at 3 in = 6,000 board feet. With 10% waste, 6,600 board feet. At a fictional yield of 4,000 board feet per set, that is 1.65 sets, so order 2.
The insulation cost per square foot is the contractor’s own total for each option divided by 2,000 SF.
What drives insulation cost per square foot?
Insulation cost per square foot depends on the type, the R-value and the access more than the area. We do not publish a national average because no sourced figure fits every product and market.
Price these drivers instead:
- Type. Fiberglass and mineral wool batts, blown cellulose or fiberglass, rigid board (polyiso, XPS, EPS, mineral wool) and spray foam all price differently.
- R-value and thickness. Higher R means thicker batts, more bags of blown-in, thicker board or more board feet of foam.
- Open or closed cell foam. Yield per set, R per inch and labor differ.
- Access and height. Lifts, attics, crawl spaces and occupied buildings slow work.
- Fasteners and adhesives. Board on walls and roofs needs fasteners, plates or adhesive.
- Air and vapor barriers. Often in the same section, sometimes in a different one.
- Fire protection. Some foam applications need a thermal or ignition barrier.
Use your own costs and the calculator gives your real cost per square foot.
What this insulation calculator does not cover
This tool calculates units for one assembly. A commercial insulation estimate covers more, and these are common gaps:
- Assemblies that change R-value or type from one wall or roof type to the next
- Framing deductions for batts in steel stud walls
- Continuous insulation at exterior walls, with fasteners and seams taped
- Under-slab and perimeter insulation at foundations
- Roof insulation and tapered systems, usually in the roofing scope
- Sound attenuation batts in interior partitions
- Firestopping, air barriers and sealants when your scope includes them
- Thermal or ignition barriers over spray foam where required
A plan-based takeoff measures each assembly from the wall, roof and floor sections. See insulation estimating for what Bidmere measures.
When an insulation estimator is not enough
A calculator works for one area and one product. A commercial bid needs every assembly measured by type, R-value and thickness.
Bidmere prepares insulation takeoffs and estimates from your plans and specifications. We measure batt, board, spray foam and blown-in insulation in square feet by assembly, R-value and thickness, and price the quantities with your rates. Single-trade estimates are from $195 and ready in 48 hours after you accept a fixed quote. You get an Excel estimate with live formulas, color-coded marked-up PDF plans, and a written list of assumptions, exclusions and open questions.
Sample takeoff
What a takeoff looks like
| Item | Quantity | Unit | Note |
|---|---|---|---|
| Batts, 106.56 SF per bag | 20 | bags | 5% waste |
| Rigid board, 4 x 8 x 2 in | 66 | EA | 4,000 BF net, 5% waste |
| Spray foam at 3 in | 6,600 | BF | 10% waste |
| Spray foam sets | 2 | sets | Fictional 4,000 BF per set |
Fictional example: 2,000 SF of exterior wall, three options
Before you send plans
Common questions about handing off the work
Why do I have to enter coverage per bag?
Coverage changes by product, size and R-value. The label is right; a generic default would be wrong.
Is calculator output enough for a commercial bid?
No. Assemblies, framing deductions and continuous insulation need a measured takeoff from the sections.
Who decides the final number?
You do. Bidmere prices quantities with your rates and you mark up and submit.
Questions
Frequently asked questions
How do you calculate insulation cost per square foot?
Total the material, labor, fasteners, equipment and access costs for one assembly. Then divide by the square feet insulated. Price each assembly separately, because a wall with batts and a roof with board will not share a cost per square foot. Enter your own prices in the insulation estimator and it does the division.
How many bags of insulation do I need?
Divide the area, plus waste, by the coverage per bag from the product label, then round up. For batts, the label lists square feet per bag. For blown-in, read the row for your target R-value on the coverage chart, since coverage per bag drops as R-value rises. The calculator does the math once you enter the coverage.
What is a board foot of spray foam?
A board foot is one square foot of material at one inch thick. So 2,000 square feet of spray foam at 3 inches is 6,000 board feet. Manufacturers give a theoretical yield per set in board feet. Real yield depends on the rig, temperature and substrate, so adjust it from your own jobs.
How do I find the thickness for a required R-value?
Divide the target R-value by the product’s R-value per inch from its data sheet. For example, a product at a fictional R-5 per inch needs 2 inches for R-10. Enter the target R and R per inch in the calculator for board or foam and it shows the thickness.
Should I deduct framing from batt insulation area?
Many estimators measure the gross wall area and let the bag coverage account for framing, because batts are sized for standard stud spacing. For nonstandard spacing or steel studs, check the product and adjust. Pick one rule and use it every time so bids stay consistent.
Does this insulation estimator store my numbers?
No. It runs in your browser and does not send or save your entries. Use the copy results button to paste the quantities, costs and inputs into your estimate, a spreadsheet or an email. Reset defaults clears your entries and restores the starting assumptions.
Can Bidmere do my insulation takeoff?
Yes. Send the plans and specifications for a free plan review and a fixed quote within 2 business hours. Single-trade insulation estimates are from $195 and ready in 48 hours after you accept. We measure by assembly, R-value and thickness and price at your rates. You pay only after you accept the price and delivery date.
For your website
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Share the project basics. You get a fixed price and delivery date within 2 business hours. Plan review is free, and you pay only after you accept.