Pipe Size Chart
NPS · DN · Schedule
NPS to DN conversion, outside diameter, wall thickness for Schedule 10-160 and XS/XXS, with inside diameter (bore) and weight per meter. Searchable by NPS, DN, or OD.
NPS vs DN — Key Facts
Smallest standard pipe. Used for instrument tubing and small connections. Sch 40 = standard weight for this size.
Small pipe for instrument air and low-flow applications. OD is 13.7mm (0.540"), not 0.250".
Small pipe for plumbing and low-pressure applications. OD 17.1mm (0.675").
Very common pipe size. Used for water lines, gas lines, and general plumbing. OD 21.3mm (0.840"). Note: NPS 1/2" OD is larger than NPS 3/8" OD.
Common residential plumbing size. OD 26.7mm (1.050"). Used for water supply lines and heating systems.
Very common pipe. OD 33.4mm (1.315") — NOT 25.4mm. Used for water, gas, steam, and general industrial piping.
Medium pipe. OD 42.2mm (1.660"). Used for plumbing and medium-flow applications.
Common medium pipe. OD 48.3mm (1.900"). Used for water supply, heating, and process piping.
One of the most common pipe sizes. OD 60.3mm (2.375"). Used for water mains, steam lines, and industrial process piping.
Medium-large pipe. OD 73.0mm (2.875"). Note: wall thickness jumps significantly at this size.
Common industrial pipe. OD 88.9mm (3.500"). Used for process piping, water distribution, and fire protection.
Very common industrial pipe. OD 114.3mm (4.500"). Used for water mains, process piping, and HVAC.
Large industrial pipe. OD 168.3mm (6.625"). Used for water distribution, process piping, and structural applications.
Large pipe for industrial and municipal applications. OD 219.1mm (8.625"). Used for water mains and process piping.
Very large pipe. OD 273.0mm (10.750"). Used for municipal water and large industrial applications.
Large municipal/industrial pipe. OD 323.8mm (12.750"). Note: NPS 12" and above, OD ≈ NPS in inches.
Sch 80 for 1/2" pipe. Thicker wall than Sch 40 (3.73 vs 2.77mm). Used for higher pressure applications. ID reduced to 13.84mm.
Sch 80 for 3/4" pipe. Wall 3.91mm vs 2.87mm (Sch 40). Higher pressure rating. ID 18.88mm.
Sch 80 for 1" pipe. Wall 4.55mm vs 3.38mm (Sch 40). Significantly higher pressure capacity. ID 24.30mm.
Sch 80 for 1-1/2" pipe. Wall 5.08mm. Used for high-pressure process piping. ID 38.14mm.
Sch 80 for 2" pipe. Wall 5.54mm vs 3.91mm (Sch 40). Common for high-pressure steam and chemical lines.
Sch 80 for 3" pipe. Wall 7.62mm. Used for high-pressure industrial applications. ID 73.66mm.
Sch 80 for 4" pipe. Wall 8.56mm. Used for high-pressure process piping and chemical applications.
Sch 80 for 6" pipe. Wall 10.97mm. Heavy wall for high-pressure applications. ID 146.36mm.
Sch 80 for 8" pipe. Wall 12.70mm. Used for high-pressure municipal and industrial piping.
Sch 10 for 1/2" pipe. Thin wall (1.65mm). Used for low-pressure applications and where weight savings matter. Stainless steel common.
Sch 10 for 3/4" pipe. Thin wall. Used for low-pressure fluid transport and food industry.
Sch 10 for 1" pipe. Very thin wall. Common in stainless steel for food, pharmaceutical, and chemical applications.
Sch 10 for 2" pipe. Thin wall. Used for low-pressure systems, drainage, and stainless steel process piping.
Sch 10 for 3" pipe. Thin wall. Common in stainless steel for food and chemical industries.
Sch 10 for 4" pipe. Thin wall. Used for low-pressure stainless steel piping systems.
Sch 10 for 6" pipe. Thin wall. Used for large-diameter low-pressure applications.
Sch 160 for 1/2" pipe. Very thick wall (4.78mm). Used for very high pressure. ID only 11.74mm — significant flow reduction.
Sch 160 for 1" pipe. Wall 6.35mm. Very high pressure rating. ID reduced to 20.70mm. Used in high-pressure hydraulic and chemical systems.
Sch 160 for 2" pipe. Wall 8.74mm. Very heavy wall. ID 42.82mm. Used for extreme pressure applications.
Sch 160 for 3" pipe. Wall 11.13mm. Extremely heavy wall. Used for very high pressure steam and chemical processes.
Sch 160 for 4" pipe. Wall 13.49mm. Very heavy wall for extreme pressure. ID 87.32mm.
Sch 160 for 6" pipe. Wall 18.26mm. Extremely heavy. Used in high-pressure power plant and refinery piping.
NPS 1/8" = DN6. OD = 10.3mm. Note: NPS is nominal — actual OD is larger than the nominal size for sizes ≤ 12".
NPS 1/4" = DN8. OD = 13.7mm. The actual OD is more than double the nominal 1/4" (6.35mm).
NPS 3/8" = DN10. OD = 17.1mm. DN10 is the metric designation used in European standards.
NPS 1/2" = DN15. OD = 21.3mm. One of the most referenced conversions. DN15 is used in EN/DIN standards.
NPS 3/4" = DN20. OD = 26.7mm. Common residential plumbing size worldwide.
NPS 1" = DN25. OD = 33.4mm. Note: OD is 1.315", not 1.000". This is the most common source of confusion in pipe sizing.
NPS 1-1/4" = DN32. OD = 42.2mm. DN32 is used in EN standards.
NPS 1-1/2" = DN40. OD = 48.3mm. Common in heating and plumbing systems.
NPS 2" = DN50. OD = 60.3mm. One of the most common industrial pipe sizes. DN50 is the European equivalent.
NPS 2-1/2" = DN65. OD = 73.0mm. Less common than 2" or 3".
NPS 3" = DN80. OD = 88.9mm. Very common industrial size. DN80 in European standards.
NPS 4" = DN100. OD = 114.3mm. One of the most common large pipe sizes. DN100 is the European equivalent.
NPS 6" = DN150. OD = 168.3mm. Common for water distribution and structural applications.
NPS 8" = DN200. OD = 219.1mm. Large industrial and municipal pipe.
NPS 10" = DN250. OD = 273.0mm. Used for large water mains and industrial piping.
NPS 12" = DN300. OD = 323.8mm. For NPS ≥ 14", OD ≈ NPS in inches. NPS 12" is the last size where OD differs significantly.
NPS 14" = DN350. OD = 355.6mm = exactly 14". From NPS 14" onward, OD = NPS in inches.
NPS 16" = DN400. OD = 406.4mm = exactly 16". Large municipal and industrial pipe.
NPS 20" = DN500. OD = 508.0mm = exactly 20". Used for major water and oil pipelines.
NPS 24" = DN600. OD = 609.6mm = exactly 24". Large-diameter pipeline for water, oil, and gas.
Pipe Size Chart Advanced Efficiency Guide
Pipe Size Chart Efficiency Optimization & Best Practices
NPS is NOT the actual diameter
The most common mistake in pipe sizing: NPS (Nominal Pipe Size) is NOT the outside diameter. For NPS ≤ 12", the OD is always larger than the nominal size. Example: NPS 2" pipe has OD 2.375" (60.3mm), not 2.000". For NPS ≥ 14", the OD equals NPS in inches (NPS 14" = OD 14.000"). The nominal size is a historical designation — always look up the actual OD from a pipe chart.
Selecting the right Schedule
Schedule 40 is the default for general applications (water, gas, low-pressure steam). Schedule 80 (XS) is used for higher pressure — wall is ~50% thicker. Schedule 10 is used for thin-wall stainless steel piping in food/pharma. Schedule 160 is for very high pressure (hydraulic, high-pressure steam). Pressure rating also depends on material: carbon steel Sch 40 NPS 2" is rated ~140 bar, while PVC Sch 40 NPS 2" is only rated ~15 bar at 20°C.
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Engineering Methodology & Design Standards: Pipe Size Chart NPS · DN · Schedule
Discipline: Fluid Mechanics, Piping Systems & Fluid Power
Governing Mathematical Formulation
In professional Fluid Mechanics, Piping Systems & Fluid Power workflows, accurate sizing and performance verification require consistent unit normalization and adherence to closed-form analytical mechanics. This Pipe Size Chart NPS · DN · Schedule utility implements the standardized engineering formulation:
Standardized parametric evaluation for Pipe Size Chart NPS · DN · ScheduleComplete pipe size chart: NPS to DN conversion, outside diameter, wall thickness for Schedule 10-160 and XS/XXS, with weight and bore data. Every input change triggers an instant client-side recalculation across all coupled dependent variables, enabling rapid sensitivity analysis during preliminary and detailed CAD design phases.
Applicable Codes, Standards & CAD Integration
Include equivalent lengths for all elbows, tees, isolation valves, and reducers extracted from your 3D piping isometric routing when evaluating total system head loss and NPSHa margin.
Engineering Verification Note: Analytical models assume homogeneous material behavior, steady-state boundary loading, and consistent dimensional units. Always apply appropriate service factors, corrosion allowances, or load and resistance factor design (LRFD / ASD) safety margins required by your governing code.
Frequently Asked Engineering Questions
Technical reference & verification guidelines for Pipe Size Chart NPS · DN · Schedule
What governing equation and methodology does the Pipe Size Chart NPS · DN · Schedule use?
The Pipe Size Chart NPS · DN · Schedule evaluates complete pipe size chart: nps to dn conversion, outside diameter, wall thickness for schedule 10-160 and xs/xxs, with weight and bore data within the Fluid Mechanics, Piping Systems & Fluid Power domain using the governing formulation: Standardized parametric evaluation for Pipe Size Chart NPS · DN · Schedule. All intermediate quantities are computed in double-precision floating-point arithmetic to prevent cumulative rounding drift before final design verification.
Which international engineering standards apply to Pipe Size Chart NPS · DN · Schedule calculations?
Calculations and boundary assumptions in this utility align with recognized industry references including Crane Technical Paper No. 410 (Flow of Fluids), ASME B31.3 (Process Piping), Hydraulic Institute ANSI/HI 9.6.1 (NPSH Margin), ISO 4413 / ISO 4414. When preparing formal calculation packages or P.E. stamp submittals, always verify local jurisdictional code amendments and project-specific safety factors.
How should I integrate results from the Pipe Size Chart NPS · DN · Schedule into my CAD or BIM workflow?
Include equivalent lengths for all elbows, tees, isolation valves, and reducers extracted from your 3D piping isometric routing when evaluating total system head loss and NPSHa margin. Using the baseline benchmark (standard nominal boundary parameters for Pipe Size Chart NPS · DN · Schedule), the solver yields verified design compliance metrics for Pipe Size Chart NPS · DN · Schedule, which can be directly cross-referenced against your parametric 3D assembly constraints, 2D fabrication drawings, or bill of materials (BOM).