REFERENCEResources / ReferenceUpdated 7 Nov 2026 · 3 min read

16 inch pipe dimensions: OD and wall thickness by schedule

Deskely Completions team Singapore

A 16 inch pipe, NPS 16 or DN 400, has an outside diameter of 406.4 mm (16.000 inches) in every schedule. From NPS 14 up the outside diameter in inches equals the nominal size. The schedule sets the wall thickness, and with it the inside diameter and the weight.

The table gives every schedule listed for NPS 16 in ASME B36.10M and B36.19M, in mm and inches.

Key takeaways
  • Outside diameter: 406.4 mm (16.000 in), the same for every schedule.
  • Schedule 40: 12.70 mm wall, 381.0 mm inside diameter.
  • Schedule 80: 21.44 mm wall, 363.5 mm inside diameter.
  • Metric equivalent: DN 400.

16 inch pipe dimensions by schedule

ScheduleWall mm (in)ID mm (in)kg/m (lb/ft)
Schedule 5S4.19 (0.165)398.02 (15.670)41.56 (27.93)
Schedule 10S4.78 (0.188)396.84 (15.624)47.34 (31.81)
Schedule 106.35 (0.250)393.70 (15.500)62.65 (42.10)
Schedule 207.92 (0.312)390.56 (15.376)77.83 (52.30)
Schedule 309.53 (0.375)387.34 (15.250)93.27 (62.68)
STD (standard)9.53 (0.375)387.34 (15.250)93.27 (62.68)
Schedule 4012.70 (0.500)381.00 (15.000)123.31 (82.86)
Schedule 6016.66 (0.656)373.08 (14.688)160.13 (107.60)
XS (extra strong)12.70 (0.500)381.00 (15.000)123.31 (82.86)
Schedule 8021.44 (0.844)363.52 (14.312)203.54 (136.78)
Schedule 10026.19 (1.031)354.02 (13.938)245.57 (165.02)
Schedule 12030.96 (1.219)344.48 (13.562)286.66 (192.62)
Schedule 14036.53 (1.438)333.34 (13.124)333.21 (223.91)
Schedule 16040.49 (1.594)325.42 (12.812)365.38 (245.52)

Nominal dimensions. Weights are for plain-end carbon steel; stainless steel is about 2 percent heavier. Mill tolerances apply, and your project pipe specification takes precedence.

16 inch pipe outside diameter

The outside diameter of NPS 16 pipe is 406.4 mm, or 16.000 inches, whatever the schedule, so 16 inch fittings and flanges fit every wall thickness. In metric drawings and specifications the same size is called DN 400.

Nearby sizes

Every size and schedule in one table: the pipe schedule chart.

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Frequently asked questions

What is the OD of 16 inch pipe?

406.4 mm (16.000 inches), the same for every schedule.

What is the wall thickness of 16 inch schedule 40 pipe?

12.70 mm (0.500 in), giving an inside diameter of 381.0 mm (15.000 in).

What is the wall thickness of 16 inch schedule 80 pipe?

21.44 mm (0.844 in), giving an inside diameter of 363.5 mm (14.312 in).

What is 16 inch pipe in DN?

DN 400.

How much does 16 inch schedule 40 pipe weigh?

123.31 kg/m (82.86 lb/ft) for plain-end carbon steel.

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