How to use
Choose NPS/DN and schedule to see outside diameter, nominal wall and calculated inside diameter in mm.
Example calculation
NPS 1 / DN 25 · 40S → D = 33.401 mm; t = 3.3782 mm; d = 26.6446 mm
Calculation method
Results use the stated subset of the sources below. Numerical conversions and limits are explicit.
d = D − 2t; 1 in = 25.4 mm
Calculation limits
DN/NPS are designations, not actual bores. Inch source dimensions are converted by 25.4; rounding can differ from metric standard tables. No tolerance or pressure rating calculation.