Steel Pipe Sizes Chart
Complete dimensional reference: NPS, DN, OD, wall thicknesses (SCH 5S through XXS), and weight per meter. Fully compliant with ASME B36.10 and B36.19 standards.
NPS / DN / OD Conversion Reference
Nominal Pipe Size (NPS) and Diameter Nominal (DN) are dimensionless designations that identify pipe size. The outside diameter (OD) is the actual physical dimension.
Important: For sizes below NPS 14 (DN 350), neither NPS nor DN equals the actual OD. For example, NPS 2 pipe has an OD of 60.3 mm, not 2 inches (50.8 mm). From NPS 14 and above, NPS equals the actual OD in inches.
| NPS (in) | DN (mm) | OD (mm) | OD (in) | NPS (in) | DN (mm) | OD (mm) | OD (in) |
|---|---|---|---|---|---|---|---|
| 1/8 | 6 | 10.3 | 0.405 | 10 | 250 | 273.1 | 10.750 |
| 1/4 | 8 | 13.7 | 0.540 | 12 | 300 | 323.9 | 12.750 |
| 3/8 | 10 | 17.1 | 0.675 | 14 | 350 | 355.6 | 14.000 |
| 1/2 | 15 | 21.3 | 0.840 | 16 | 400 | 406.4 | 16.000 |
| 3/4 | 20 | 26.7 | 1.050 | 18 | 450 | 457.2 | 18.000 |
| 1 | 25 | 33.4 | 1.315 | 20 | 500 | 508.0 | 20.000 |
| 1-1/4 | 32 | 42.2 | 1.660 | 24 | 600 | 610.0 | 24.000 |
| 1-1/2 | 40 | 48.3 | 1.900 | 30 | 750 | 762.0 | 30.000 |
| 2 | 50 | 60.3 | 2.375 | 36 | 900 | 914.4 | 36.000 |
| 2-1/2 | 65 | 73.0 | 2.875 | 42 | 1050 | 1066.8 | 42.000 |
| 3 | 80 | 88.9 | 3.500 | 48 | 1200 | 1219.2 | 48.000 |
| 4 | 100 | 114.3 | 4.500 | 56 | 1400 | 1422.4 | 56.000 |
| 6 | 150 | 168.3 | 6.625 | 64 | 1600 | 1625.6 | 64.000 |
| 8 | 200 | 219.1 | 8.625 | 72 | 1800 | 1828.8 | 72.000 |
Pipe Schedule Wall Thickness Chart (mm) - ASME B36.10
Wall thickness values in millimeters for carbon and alloy steel pipes per ASME B36.10. STD (Standard) equals Sch 40 for NPS 1/8 to 10; XS (Extra Strong) equals Sch 80 for NPS 1/8 to 8.
Showing all
| NPS | DN | OD (mm) | Sch 5S | Sch 10S | Sch 10 | Sch 20 | Sch 30 | Sch 40/STD | Sch 60 | Sch 80/XS | Sch 100 | Sch 120 | Sch 140 | Sch 160 | XXS |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1/8 | 6 | 10.3 | 1.24 | 1.24 | 1.73 | — | — | 1.73 | — | 2.41 | — | — | — | — | — |
| 1/4 | 8 | 13.7 | 1.65 | 1.65 | 2.24 | — | — | 2.24 | — | 3.02 | — | — | — | — | — |
| 3/8 | 10 | 17.1 | 1.65 | 1.65 | 2.31 | — | — | 2.31 | — | 3.20 | — | — | — | — | — |
| 1/2 | 15 | 21.3 | 1.65 | 2.11 | 2.11 | — | — | 2.77 | — | 3.73 | — | — | — | 4.78 | 7.47 |
| 3/4 | 20 | 26.7 | 1.65 | 2.11 | 2.11 | — | — | 2.87 | — | 3.91 | — | — | — | 5.56 | 7.82 |
| 1 | 25 | 33.4 | 1.65 | 2.77 | 2.77 | — | — | 3.38 | — | 4.55 | — | — | — | 6.35 | 9.09 |
| 1-1/4 | 32 | 42.2 | 1.65 | 2.77 | 2.77 | — | — | 3.56 | — | 4.85 | — | — | — | 6.35 | 9.70 |
| 1-1/2 | 40 | 48.3 | 1.65 | 2.77 | 2.77 | — | — | 3.68 | — | 5.08 | — | — | — | 7.14 | 10.15 |
| 2 | 50 | 60.3 | 1.65 | 2.77 | 2.77 | — | — | 3.91 | — | 5.54 | — | — | — | 8.74 | 11.07 |
| 2-1/2 | 65 | 73.0 | 2.11 | 3.05 | 3.05 | — | — | 5.16 | — | 7.01 | — | — | — | 9.53 | 14.02 |
| 3 | 80 | 88.9 | 2.11 | 3.05 | 3.05 | — | — | 5.49 | — | 7.62 | — | — | — | 11.13 | 15.24 |
| 3-1/2 | 90 | 101.6 | 2.11 | 3.05 | 3.05 | — | — | 5.74 | — | 8.08 | — | — | — | — | 16.15 |
| 4 | 100 | 114.3 | 2.11 | 3.05 | 3.05 | — | — | 6.02 | — | 8.56 | — | 11.13 | — | 13.49 | 17.12 |
| 5 | 125 | 141.3 | 2.77 | 3.40 | 3.40 | — | — | 6.55 | — | 9.53 | — | 12.70 | — | 15.88 | 19.05 |
| 6 | 150 | 168.3 | 2.77 | 3.40 | 3.40 | — | — | 7.11 | — | 10.97 | — | 14.27 | — | 18.26 | 21.95 |
| 8 | 200 | 219.1 | 2.77 | 3.76 | 3.76 | 6.35 | 7.04 | 8.18 | 10.31 | 12.70 | 15.09 | 18.26 | 20.62 | 23.01 | 22.23 |
| 10 | 250 | 273.1 | 3.40 | 4.19 | 4.19 | 6.35 | 7.80 | 9.27 | 12.70 | 12.70 | 18.26 | 21.44 | 25.40 | 28.58 | 25.40 |
| 12 | 300 | 323.9 | 3.96 | 4.57 | 4.57 | 6.35 | 8.38 | 9.53 | 14.27 | 12.70 | 21.44 | 25.40 | 28.58 | 33.32 | 25.40 |
| 14 | 350 | 355.6 | 3.96 | 4.78 | 6.35 | 7.92 | 9.53 | 9.53 | 15.09 | 12.70 | 23.83 | 27.79 | 31.75 | 35.71 | — |
| 16 | 400 | 406.4 | 4.19 | 4.78 | 6.35 | 7.92 | 9.53 | 9.53 | 16.66 | 12.70 | 26.19 | 30.96 | 36.53 | 40.49 | — |
| 18 | 450 | 457.2 | 4.19 | 4.78 | 6.35 | 7.92 | 11.13 | 9.53 | 18.26 | 12.70 | 29.36 | 34.93 | 39.67 | 45.24 | — |
| 20 | 500 | 508.0 | 4.78 | 5.54 | 6.35 | 9.53 | 12.70 | 9.53 | 20.62 | 12.70 | 32.54 | 38.10 | 44.45 | 50.01 | — |
| 24 | 600 | 609.6 | 5.54 | 6.35 | 6.35 | 9.53 | 14.27 | 9.53 | 24.61 | 12.70 | 38.89 | 46.02 | 52.37 | 59.54 | — |
Note: Sch 5S and Sch 10S are primarily used for stainless steel pipes per ASME B36.19. Wall thicknesses of 6.35 mm and above are rounded to two decimal places.
Carbon Steel Pipe Weight Chart (kg/m) - ASME B36.10
Weight per meter for carbon steel pipes (density 7,850 kg/m³). Most commonly used schedules shown.
| NPS | DN | OD (mm) | Sch 10 | Sch 20 | Sch 40/STD | Sch 60 | Sch 80/XS | Sch 100 | Sch 120 | Sch 140 | Sch 160 | XXS |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1/8 | 6 | 10.3 | 0.37 | — | 0.37 | — | 0.47 | — | — | — | — | — |
| 1/4 | 8 | 13.7 | 0.63 | — | 0.63 | — | 0.80 | — | — | — | — | — |
| 3/8 | 10 | 17.1 | 0.80 | — | 0.80 | — | 1.10 | — | — | — | — | — |
| 1/2 | 15 | 21.3 | 1.01 | — | 1.27 | — | 1.62 | — | — | — | 1.95 | 2.55 |
| 3/4 | 20 | 26.7 | 1.28 | — | 1.69 | — | 2.20 | — | — | — | 2.98 | 3.64 |
| 1 | 25 | 33.4 | 2.09 | — | 2.50 | — | 3.24 | — | — | — | 4.24 | 5.45 |
| 1-1/4 | 32 | 42.2 | 2.69 | — | 3.39 | — | 4.47 | — | — | — | 5.41 | 7.77 |
| 1-1/2 | 40 | 48.3 | 3.11 | — | 4.05 | — | 5.41 | — | — | — | 7.25 | 9.56 |
| 2 | 50 | 60.3 | 3.93 | — | 5.44 | — | 7.48 | — | — | — | 11.11 | 13.44 |
| 2-1/2 | 65 | 73.0 | 5.26 | — | 8.63 | — | 11.41 | — | — | — | 14.92 | 20.39 |
| 3 | 80 | 88.9 | 6.45 | — | 11.29 | — | 15.27 | — | — | — | 21.35 | 27.68 |
| 4 | 100 | 114.3 | 8.37 | — | 16.07 | — | 22.32 | — | — | — | 33.54 | 41.03 |
| 5 | 125 | 141.3 | 11.57 | — | 21.77 | — | 30.97 | — | — | — | 49.12 | 57.44 |
| 6 | 150 | 168.3 | 13.84 | — | 28.26 | — | 42.56 | — | — | — | 67.57 | 79.22 |
| 8 | 200 | 219.1 | 19.98 | 33.31 | 42.55 | 53.08 | 64.64 | 75.92 | 90.44 | 100.95 | 111.26 | 107.88 |
| 10 | 250 | 273.1 | 27.79 | 41.76 | 60.31 | 81.55 | 81.55 | 114.77 | 133.13 | 155.14 | 172.33 | 155.14 |
| 12 | 300 | 323.9 | 36.02 | 49.71 | 73.86 | 108.96 | 97.44 | 160.06 | 186.97 | 208.15 | 238.76 | 186.97 |
| 14 | 350 | 355.6 | 54.76 | 67.90 | 81.33 | 126.71 | 107.39 | 195.00 | 224.66 | 253.55 | 281.70 | — |
| 16 | 400 | 406.4 | 62.64 | 77.83 | 93.27 | 160.12 | 123.30 | 245.47 | 286.54 | 333.18 | 365.35 | — |
| 18 | 450 | 457.2 | 70.61 | 87.75 | 105.21 | 197.60 | 139.20 | 309.66 | 363.57 | 408.33 | 459.41 | — |
| 20 | 500 | 508.0 | 78.55 | 117.15 | 117.15 | 247.81 | 155.12 | 381.55 | 441.49 | 508.08 | 564.74 | — |
| 24 | 600 | 609.6 | 94.45 | 140.97 | 140.97 | 355.06 | 186.90 | 547.32 | 639.49 | 719.83 | 807.62 | — |
Formula: Weight (kg/m) = (OD - WT) × WT × 0.02466. For stainless steel (density 7,930 kg/m³), multiply by 1.01.
Stainless Steel Pipe Sizes - ASME B36.19
Common wall thicknesses for stainless steel pipes. ASME B36.19 uses the same OD as ASME B36.10 but with different schedule designations (Sch 5S, 10S, 40S, 80S).
| NPS | DN | OD (mm) | Sch 5S (mm) | Sch 10S (mm) | Sch 40S (mm) | Sch 80S (mm) | Sch 160 (mm) |
|---|---|---|---|---|---|---|---|
| 1/8 | 6 | 10.3 | 1.24 | 1.24 | 1.73 | 2.41 | — |
| 1/4 | 8 | 13.7 | 1.65 | 1.65 | 2.24 | 3.02 | — |
| 3/8 | 10 | 17.1 | 1.65 | 1.65 | 2.31 | 3.20 | — |
| 1/2 | 15 | 21.3 | 1.65 | 2.11 | 2.77 | 3.73 | 4.78 |
| 3/4 | 20 | 26.7 | 1.65 | 2.11 | 2.87 | 3.91 | 5.56 |
| 1 | 25 | 33.4 | 1.65 | 2.77 | 3.38 | 4.55 | 6.35 |
| 1-1/4 | 32 | 42.2 | 1.65 | 2.77 | 3.56 | 4.85 | 6.35 |
| 1-1/2 | 40 | 48.3 | 1.65 | 2.77 | 3.68 | 5.08 | 7.14 |
| 2 | 50 | 60.3 | 1.65 | 2.77 | 3.91 | 5.54 | 8.74 |
| 2-1/2 | 65 | 73.0 | 2.11 | 3.05 | 5.16 | 7.01 | 9.53 |
| 3 | 80 | 88.9 | 2.11 | 3.05 | 5.49 | 7.62 | 11.13 |
| 4 | 100 | 114.3 | 2.11 | 3.05 | 6.02 | 8.56 | 13.49 |
| 6 | 150 | 168.3 | 2.77 | 3.40 | 7.11 | 10.97 | 18.26 |
| 8 | 200 | 219.1 | 2.77 | 3.76 | 8.18 | 12.70 | 23.01 |
| 10 | 250 | 273.1 | 3.40 | 4.19 | 9.27 | 12.70 | 28.58 |
| 12 | 300 | 323.9 | 3.96 | 4.57 | 9.53 | 12.70 | 33.32 |
Common Steel Pipe Standards & Specifications
Steel pipes are manufactured under various international standards based on application and material requirements.
| Standard | Material | Size Range | Application |
|---|---|---|---|
| ASTM A53 | Carbon Steel (Welded/Seamless) | NPS 1/8" – 26" | General mechanical, pressure, steam |
| ASTM A106 | Carbon Steel (Seamless) | NPS 1/8" – 48" | High-temperature service |
| API 5L | Carbon/Alloy Steel (Welded/Seamless) | NPS 1/2" – 80" | Oil & gas transmission pipelines |
| ASTM A312 | Stainless Steel (Seamless/Welded) | NPS 1/8" – 30" | Corrosive service, chemical plants |
| ASTM A333 | Carbon/Alloy Steel (Seamless/Welded) | NPS 1/8" – 36" | Low-temperature service (down to -195°C) |
| ASTM A335 | Alloy Steel (Seamless) | NPS 1/8" – 48" | High-temperature service (power plants) |
ASME B36.10 vs B36.19
ASME B36.10 covers carbon and alloy steel pipe dimensions. ASME B36.19 covers stainless steel pipe dimensions. Both standards use the same outside diameters for a given NPS, ensuring compatibility with the same flanges, fittings, and supports.
Frequently Asked Questions
What is the difference between NPS and DN?
NPS (Nominal Pipe Size) is the North American designation in inches. DN (Diameter Nominal) is the metric equivalent in millimeters. Both are dimensionless labels; neither equals the actual outside diameter for sizes below NPS 14/DN 350. For example, NPS 2 and DN 50 both refer to the same pipe with an OD of 60.3 mm.
What does "Schedule" (Sch) mean?
Pipe schedule (Sch) indicates wall thickness. Higher schedule numbers indicate thicker walls and higher pressure ratings. Common schedules: Sch 40 (standard weight), Sch 80 (extra strong), Sch 160 (double extra strong), and XXS. For NPS 1/8" to 10", STD equals Sch 40 and XS equals Sch 80.
Why doesn't NPS equal the actual outside diameter?
Historically, pipe sizes were named based on approximate inside diameter (bore). When manufacturing techniques improved and wall thicknesses were standardized, the OD was fixed while the ID varied with wall thickness. The name (NPS) remained but no longer matches the actual measurement. From NPS 14 and above, NPS equals the actual OD in inches.
What is the OD of a 2-inch steel pipe?
The outside diameter of NPS 2 pipe is 2.375 inches (60.3 mm). This OD is constant regardless of schedule (wall thickness). Only the inside diameter (ID) changes with different wall thicknesses.
What is the difference between Sch 40 and Sch 80?
Sch 80 has a thicker wall than Sch 40 for the same NPS. For example, NPS 2 Sch 40 has a wall thickness of 3.91 mm (weight 5.44 kg/m), while Sch 80 has 5.54 mm (weight 7.48 kg/m). The OD remains 60.3 mm; the ID decreases from 52.5 mm to 49.2 mm.
How is steel pipe weight calculated?
Weight per meter (kg/m) = (OD - WT) × WT × 0.02466, where OD and WT are in millimeters. The constant 0.02466 is derived from steel density (7,850 kg/m³) × π / 1000. For stainless steel (7,930 kg/m³), use 0.02491.
