01
Formula
Board feet = square feet × inches ÷ 12.
R-value = inches × R per inch. Rolls = square feet ÷ coverage per roll, rounded up. Cost is board feet times your price per board foot, or whole rolls times your price per roll.
Apply for financingInsulation calculator
Insulation calculator for foam, batts, and R-value
This insulation calculator estimates spray foam in board feet or batt rolls from the area. R-value is thickness times the R per inch you take from the product sheet. It is an insulation R value calculator only for that product number.
Product
Board feet
166.67bd ft
R-value at this thickness13.00
Estimated material cost$250.00
Planning estimate from the numbers you enter. Coverage, density, waste and price are assumptions, not a supplier quote or an engineering specification.
How it works
A board foot of foam is one square foot, one inch thick.
Board feet equal area in square feet times thickness in inches, divided by 12. That is the spray foam board feet calculator. Rolls equal area divided by the square feet printed on the roll, rounded up. R-value equals thickness times R per inch. The foam example starts at 6.5 R per inch so the arithmetic is visible. That number is an input, not a claim that every foam is R-6.5. Read the sheet for the product you are buying. The insulation calculator does not decide vapor barriers, ignition barriers, or code R for a climate zone.
02
Example
1,000 square feet of foam at 2 inches.
That is 166.67 board feet. At 6.5 R per inch the assembly is R-13.00, if the sheet really says 6.5. At $1.50 per board foot the material is $250.00. Switch to batts and enter the square feet per roll from the package.
03
Tips
Do not borrow an R per inch from a different product.
Batts, open-cell foam, and closed-cell foam are not interchangeable in this field. A spray foam calculator result in board feet is volume. The R line is only as good as the R per inch you typed.
04
Equipment
The rig is separate from the board feet.
Spray rigs and other job equipment can be financed through Dengaro from $15,000 to $2 million. The board-foot count is material math, not the machine price.
Important questions
Know what to expect.
How does the spray foam board feet calculator define a board foot?+
One board foot is 12 inches by 12 inches by 1 inch. Two inches over one square foot is two board feet. One thousand square feet at two inches is 166.67 board feet.
Where do I get the number for the insulation R value calculator?+
From the product data sheet, as R per inch or as R for a stated thickness. If the sheet gives R for a thickness, divide that R by the inches to fill R per inch, or compare the sheet's R with the result.
Do batts use board feet?+
This page counts batts in rolls, using the coverage on the package. Board feet stay on the spray foam setting. The R-value line still uses thickness and R per inch.
Does this meet a code R-value?+
It does not know the code or the climate. It multiplies the thickness by the R per inch you entered. Compare that product R with the requirement that applies to the assembly.
Financing built into the sale