Work out insulation quantity instantly with clear inputs, formula shown and shareable results.
Insulation quantity is area divided by pack coverage with a small cutting allowance. The thermal benefit is the R-value, thickness in metres divided by conductivity, so 100 mm of mineral wool at 0.035 W/m·K gives 2.86 m²·K/W. The U-value of that layer alone is the reciprocal.
Quantity
Packs = ceil(area x 1.05 / coverage per pack)
Thermal resistance
R = thickness m / conductivity; U of the layer = 1 / R
Packs = ceil(area x 1.05 / coverage per pack). Insulation quantity is area divided by pack coverage with a small cutting allowance.
Framing members bridge the insulation, and air films and other layers add resistance. A framed wall with 15 percent timber fraction loses a noticeable share of the insulation's benefit.
This calculator takes 4 inputs: Area to insulate, Insulation thickness, Coverage per roll or pack, Thermal conductivity. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.