Calculator
Pipe Wall Thickness Calculator
Calculate the minimum required pipe wall thickness for a given pressure, diameter, and material using the Barlow formula, with a corrosion allowance.
Interactive toolUpdated July 2026
Inputs
Carbon steel ≈ 138, stainless ≈ 138, copper ≈ 70.
1.0 seamless, 0.85 ERW, 0.60 furnace butt-weld.
Results
Required Wall Thickness
3.571 mm
pressure wall 2.071 mm + corrosion 1.500 mm
How It Works
t = (P · D) / (2 · S · E) + C
Barlow formula. P = design pressure (MPa), D = OD (mm), S = allowable stress (MPa), E = joint efficiency, C = corrosion allowance (mm).
This is a preliminary Barlow calculation. Refer to the governing code (AS 4041, ASME B31.3, API 5L) for mandatory wall thickness, which includes design factors, temperature derating, and mill tolerance.