Insulation · Project planning

Batt Insulation Calculator

Order batts by labeled pack coverage or by the number of pieces needed for individual cavities. Piece mode prevents area-only counts from overlooking short offcuts.

By Alish Gautam, Software Developer · Updated · Calculation methodology

Start with the editable example below. Dimensions retain their physical size when units change. Region sets currency labels without converting currencies; confirm entered quotes after changing region. Thermal inputs labeled US R retain that unit in every region.

Measured insulation surfaces

Use non-overlapping rectangles. Enter openings as area on the surface they interrupt.

Room / surface 1
Basic settings
Choose the estimating method.
Product settings
Product and system dimensions
Editable arithmetic example. Replace with your project or product specification.
Optional supplier product name, chart revision or quote reference, saved in shared project state.
Advanced settings
Advanced planning settings
Planning allowance, not a code or industry requirement. Set zero to order the exact rounded takeoff.
Cost settings · USD
Optional quote prices
Optional supplier quote in the selected currency. Blank omits cost.

Project takeoff

Whole packages round up. Allowance is separate from purchased surplus. Prices omit labor, delivery, tax and other items unless explicitly entered.

Gross measured area
120 ft²
Opening / exclusion deductions
0 ft²
Net requirement
120 ft²
Allowance
12 ft²
Planned requirement
132 ft²
Unrounded package requirement
3.3
Packs / units to buy
4
Purchased coverage
160 ft²
Surplus beyond planned requirement
28 ft²

Supplier-ready material list

Packs / units to buy
4
Geometry / layout breakdown
Dimensions use the selected measurement system.
SurfaceMaterialGross (ft²)Net (ft²)
Room / surface 1floor120120

Piece mode assumes no offcut reuse between cavities. Fit, compression, facing orientation and cavity depth must follow the actual product instructions.

How it works

Piece count = cavities × ceil(cavity width / batt width) × ceil(cavity length / batt length). Whole packs round after a separate piece allowance.

Assumptions and limitations

Piece mode assumes no offcut reuse between cavities. Fit, compression, facing orientation and cavity depth must follow the actual product instructions.

Whole packages round upward after the chosen allowance. Physical geometry and purchase reserve are separate. Manufacturer and project specifications override editable examples; the selected region does not establish a local code requirement.

Sources and boundaries

ROCKWOOL: COMFORTBATT

Open the source · Product page · Reference checked 2026-10-04

Scope: Manufacturer batt product documentation

Used for: Obtain exact batt dimensions and pack coverage.

Does not establish: Generic mineral-wool package dimensions.

Use the current product document to verify numerical inputs. Use the package SKU and labeled coverage.