Insulation Calculator

Free

Insulation · Batt, blown, rigid board and spray foam · default waste 5%

Enter your measurements

Numbers start at typical defaults — change anything. Every result states the inputs and assumptions used.

Application

Length (run)(ft)

Height (or width)(ft)

Openings to deduct(sq ft)

Insulation type

Thickness (installed)(in)

Installed thickness, entered directly. Spray foam is costed from this thickness: board feet = net area × thickness.

R-value (as labelled)

Waste factor(%)

Applied once to each material quantity, then rounded up to the orderable increment.

Product assumptions — editable1

Sheet sizes, coverage rates, bundle counts, bag yield and similar come from the product you are buying. Change any of them to match your supplier — whatever you set is shown again with the result.

Coverage per package / sheet(sq ft)

Batt: sq ft per bag. Blown: sq ft per bag at your R-value. Rigid board: sq ft per sheet. Take this from the product label or supplier chart.

Enter your measurements and press "Calculate materials" to see the calculated quantity, waste-adjusted quantity and recommended order quantity.

What this calculator does

•Coverage path (batt, roll, mineral wool, blown-in, rigid board): packages = net area ÷ coverage per package
•Spray foam path: board feet = net area × installed thickness
•Spray foam path: kits = board feet ÷ product yield per kit
•Recommended order = quantity + waste, rounded up to whole packages or kits

Deterministic by design: no AI, no lookups, no network calls — the same inputs always give the same numbers. Product values such as coverage rates and bundle counts are editable and shown with the result.