Tool · web calculator

Insulation / lagging m² estimator

Pick pipe or duct size, length and thickness. Get net m² plus an allowance. Symbols label each shape so the choice is clear without relying on colour alone.

Shape

Result

Round duct Ø250 mm + 25 mm wrap

Outer perimeter
0.942 m
Net wrap area
9.42 m²
With 10% allowance
≈ 10.37 m²

Formula: outer surface after wrap (diameter or sides + 2×thickness) × length × (1 + allowance). Estimate only — check manufacturer cut sheets for bends, fittings and overlaps.