Insulation Calculators

The deterministic R-value & quantity cluster — the highest-demand insulation queries: an R-value calculator (assembly R = sum of layers, R/inch by material), an insulation thickness / required-R calculator, a U-value ↔ R-value converter, a batt bundle calculator, a blown-in bag calculator (coverage-per-bag-at-R or by depth), a spray-foam board-feet & set/kit calculator, a rigid-foam board / sheet calculator, a climate-zone target-R reference, and an insulation removal / add-over calculator. R/inch and target R are labeled published typicals, not a certified design — follow the data sheet and local energy code.

Confirm coverage-per-bag, R-per-inch and set yield against the exact product you buy and order a little extra (~5–10%) for framing, gaps and settling. Coverage, R/inch and set yields vary by product and brand — read the bag/kit and the data sheet.
Typical published planning values — NOT a certified design. Real performance depends on installation quality, framing / thermal bridging, moisture and settling; follow the product data sheet and your local energy code. Foam ignition/thermal-barrier, vapor/moisture control and combustion-air safety are set by the manufacturer and code — check with a professional.
R-value calculatorAdd insulation layers in series to get the total assembly R-value and U-value. Enter thickness and R per inch for each layer, add air films, done.Insulation thickness calculatorFind how many inches of insulation you need to reach a target R-value. Enter your target R and the material R per inch to get the required depth.U-value ↔ R-value converterConvert R-value to U-value and back in one step. U is thermal conductance, R is resistance, and they are exact reciprocals: U = 1 ÷ R and R = 1 ÷ U.Batt insulation calculatorWork out how many batt insulation bundles to buy. Enter the area and the coverage per bundle, add a waste allowance, and get the bundle count rounded up.Blown-in insulation calculatorCalculate how many bags of blown-in insulation you need. Choose the coverage-per-bag-at-R chart or the depth (board-feet) method for your attic square footage.Spray-foam board-feet & set calculatorCalculate spray foam board-feet and how many kits or sets you need. Board-feet = area × thickness; sets = board-feet ÷ the labeled yield per kit, rounded up.Rigid-foam board / sheet calculatorCount rigid foam board sheets and find the R-value. Sheets = area ÷ 32 (a 4×8 sheet), and board R = thickness × R per inch for EPS, XPS or polyiso.Climate-zone target-R referenceLook up the target R-value for your IECC climate zone and assembly. Typical attic, wall-cavity and floor R-value bands for zones 1 through 8.Insulation removal / add-over calculatorSee how much insulation to add over existing to reach a target R-value. Added depth = (target R − existing R) ÷ R per inch, with the new total R.

Every Insulation Calculators tool is calculated server-side — visible immediately — with its formula, a worked example and a reference table, and works on the measurements you take and the prices you enter from your own quotes. Background reading is in the guides.