API Casing and Tubing Size Chart
Jun 02, 2026
According to the API Spec 5CT (Specification for Casing and Tubing), API Casing and Tubing are collectively referred to as Oil Country Tubular Goods (OCTG) and serve as critical components for ensuring wellbore structural integrity and providing fluid production conduits; casing is primarily used to line the wellbore, isolate formations with varying pressures, and prevent borehole collapse, while tubing is installed within the casing to transport oil and gas to the surface or facilitate injection and production operations.
Their standard outside diameter (OD) ranges are extensive, with tubing typically covering 1.050 inches (26.7 mm) to 4-1/2 inches (114.3 mm) and casing ranging from 4-1/2 inches (114.3 mm) up to 20 inches (508 mm), utilized in conjunction with various steel grades and thread connections based on well depth and geological conditions.
API Casing and Tubing Size Chart
API Tubing Dimensions and Weight Chart
| DN | O. D. | Weight | W. T. | End Processing | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Non-upset | Upset | Steel Grade | |||||||||||
| coupling-thread | coupling-thread | ||||||||||||
| Inch | mm | lb./ft. | lb./ft. | Inch | mm | H40 | J55 | L80 | N80 | C90 | T95 | P110 | |
| 2 3/8 | 2.375 | 60.32 | 4 | – | 0.167 | 4.24 | PU | PN | PN | PN | PN | PN | – |
| 4.6 | 4.7 | 0.19 | 4.83 | PNU | PNU | PNU | PNU | PNU | PNU | PNU | |||
| 5.8 | 5.95 | 0.254 | 6.45 | – | – | PNU | PNU | PNU | PNU | PNU | |||
| 6.6 | – | 0.295 | 7.49 | – | – | P | – | P | P | – | |||
| 7.35 | 7.45 | 0.336 | 8.53 | – | – | PU | – | PU | PU | – | |||
| 2 7/8 | 2.875 | 73.02 | 6.4 | 6.5 | 0.217 | 5.51 | PNU | PNU | – | – | – | – | – |
| 7.8 | 7.9 | 0.276 | 7.01 | – | – | – | – | – | – | – | |||
| 8.6 | 8.7 | 0.308 | 7.82 | – | – | PLB | PLB | PLBE | – | PLB | |||
| 9.35 | 9.45 | 0.34 | 8.64 | – | – | PLB | PLB | PLBE | – | PLB | |||
| 10.5 | – | 0.392 | 9.96 | – | – | PLB | PLB | PLB | – | PLB | |||
| 11.5 | – | 0.44 | 11.18 | – | – | – | – | PLB | – | ||||
| 3 1/2 | 3.5 | 88.9 | 7.7 | – | 0.216 | 5.49 | PN | PN | PN | PN | PN | PN | – |
| 9.2 | 9.3 | 0.254 | 6.45 | PNU | PNU | PNU | PNU | PNU | PNU | PNU | |||
| 10.2 | – | 0.289 | 7.34 | PN | PN | PN | PN | PN | PN | – | |||
| 12.7 | 12.95 | 0.375 | 9.52 | – | – | PNU | PNU | PNU | PNU | PNU | |||
| 14.3 | – | 0.43 | 10.92 | – | – | P | – | P | P | – | |||
| 15.5 | – | 0.476 | 12.09 | – | – | P | – | P | P | – | |||
| 17 | – | 0.53 | 13.46 | – | – | P | – | P | P | – | |||
| 4 | 4 | 101.6 | 9.5 | – | 0.226 | 5.74 | PN | PN | PN | PN | PN | PN | – |
| – | 11 | 0.262 | 6.65 | PU | PU | PU | PU | PU | PU | – | |||
| 13.2 | – | 0.33 | 8.38 | – | – | P | – | P | P | – | |||
| 16.1 | – | 0.415 | 10.54 | – | – | P | – | P | P | – | |||
| 18.9 | – | 0.5 | 12.7 | – | – | P | – | P | P | – | |||
| 22.2 | – | 0.61 | 15.49 | – | – | P | – | P | P | – | |||
| 4 1/2 | 4.5 | 114.3 | 12.6 | 12.75 | 0.271 | 6.88 | PNU | PNU | PNU | PNU | PNU | PNU | – |
| 15.2 | – | 0.337 | 8.56 | – | – | P | – | P | P | – | |||
| 17 | – | 0.38 | 9.65 | – | – | P | – | P | P | – | |||
| 18.9 | – | 0.43 | 10.92 | – | – | P | – | P | P | PLB | |||
| 21.5 | – | 0.5 | 12.7 | – | – | P | – | P | P | PLB | |||
| 23.7 | – | 0.56 | 14.22 | – | – | P | – | P | P | PLB | |||
| 26.1 | – | 0.63 | 16 | – | – | P | – | P | P | PLB | |||
| P--Plain;N-- Non-upset coupling-thread;U-- Upset coupling-thread; L--Integral | |||||||||||||
API Casing Pipe Dimensions and Weight Chart
| DN | O. D. | Weight | W. T. | End Machining Form | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Steel Grade | ||||||||||||
| Inch | mm | lb/ft | kg/m | Inch | mm | H40 | J55 | L80 | N80 | C90 | P110 | |
| K55 | T95 | |||||||||||
| 4 1/2 | 4.5 | 114.3 | 9.5 | 14.14 | 0.205 | 5.21 | PS | PS | – | – | – | – |
| 10.5 | 15.63 | 0.224 | 5.69 | – | PSB | – | – | – | – | |||
| 11.6 | 17.26 | 0.25 | 6.35 | – | PSLB | PLB | PLB | PLB | PLB | |||
| 13.5 | 20.09 | 0.29 | 7.37 | – | – | PLB | PLB | PLB | PLB | |||
| 15.1 | 22.47 | 0.337 | 9.56 | – | – | – | – | – | PLB | |||
| 5 | 5 | 127 | 11.5 | 17.11 | 0.22 | 5.59 | – | PS | – | – | – | – |
| 13 | 19.35 | 0.253 | 6.43 | – | PSLB | – | – | – | – | |||
| 15 | 22.32 | 0.296 | 7.52 | – | PSLB | PLB | PLB | PLBE | PLB | |||
| 18 | 26.79 | 0.362 | 9.19 | – | – | PLB | PLB | PLBE | PLB | |||
| 21.4 | 31.85 | 0.437 | 11.1 | – | – | PLB | PLB | PLB | PLB | |||
| 23.2 | 34.53 | 0.478 | 12.14 | – | – | – | – | PLB | – | |||
| 24.1 | 35.86 | 0.5 | 12.7 | – | – | – | – | PLB | – | |||
| 5 1/2 | 5.5 | 139.7 | 14 | 20.83 | 0.244 | 6.2 | PS | PS | – | – | – | – |
| 15.5 | 23.07 | 0.275 | 6.98 | – | PSLB | – | – | – | – | |||
| 17 | 25.3 | 0.304 | 7.72 | – | PSLB | PLB | PLB | PLBE | PLB | |||
| 20 | 29.76 | 0.361 | 9.17 | – | – | PLB | PLB | PLBE | PLB | |||
| 23 | 34.23 | 0.415 | 10.54 | – | – | PLB | PLB | PLBE | PLB | |||
| 26.8 | 39.88 | 0.5 | 12.7 | – | – | – | – | – | – | |||
| 29.7 | 44.2 | 0.562 | 14.27 | – | – | – | – | – | – | |||
| 32.6 | 48.51 | 0.625 | 15.88 | – | – | – | – | – | – | |||
| 35.3 | 52.53 | 0.687 | 17.45 | – | – | – | – | – | – | |||
| 38 | 56.55 | 0.75 | 19.05 | – | – | – | – | – | – | |||
| 40.5 | 60.27 | 0.812 | 20.62 | – | – | – | – | – | – | |||
| 43.1 | 64.14 | 0.875 | 22.22 | – | – | – | – | – | – | |||
| 6 5/8 | 6.625 | 168.28 | 20 | 29.76 | 0.288 | 7.32 | PS | PSLB | – | – | – | – |
| 24 | 35.72 | 0.352 | 8.94 | – | PSLB | PLB | PLB | PLBE | PLB | |||
| 28 | 41.67 | 0.417 | 10.59 | – | – | PLB | PLB | PLBE | PLB | |||
| 32 | 47.62 | 0.475 | 12.06 | – | – | PLB | PLB | PLBE | PLB | |||
| 7 | 7 | 177.8 | 17 | 25.3 | 0.231 | 5.87 | PS | – | – | – | – | – |
| 20 | 29.76 | 0.272 | 6.91 | PS | PS | – | – | – | – | |||
| 23 | 34.23 | 0.317 | 8.05 | – | PSLB | PLB | PLB | PLBE | – | |||
| 26 | 38.69 | 0.362 | 9.19 | – | PSLB | PLB | PLB | PLBE | PLB | |||
| 29 | 43.16 | 0.408 | 10.36 | – | – | PLB | PLB | PLBE | PLB | |||
| 32 | 47.62 | 0.453 | 11.51 | – | – | PLB | PLB | PLBE | PLB | |||
| 35 | 52.09 | 0.498 | 12.65 | – | – | PLB | PLB | PLBE | PLB | |||
| 38 | 56.55 | 0.54 | 13.72 | – | – | PLB | PLB | PLBE | PLB | |||
| 42.7 | 63.54 | 0.625 | 15.88 | – | – | – | – | – | – | |||
| 46.4 | 69.05 | 0.687 | 17.45 | – | – | – | – | – | – | |||
| 50.1 | 74.56 | 0.75 | 19.05 | – | – | – | – | – | – | |||
| 53.6 | 79.77 | 0.812 | 20.62 | – | – | – | – | – | – | |||
| 57.1 | 84.97 | 0.875 | 22.22 | – | – | – | – | – | – | |||
| 7 5/8 | 7.625 | 193.68 | 24 | 35.72 | 0.3 | 7.62 | PS | – | – | – | – | – |
| 26.4 | 39.29 | 0.328 | 8.33 | – | PSLB | PLB | PLB | PLBE | PLB | |||
| 29.7 | 44.2 | 0.375 | 9.52 | – | – | PLB | PLB | PLBE | PLB | |||
| 33.7 | 50.15 | 0.43 | 10.92 | – | – | PLB | PLB | PLBE | PLB | |||
| 39 | 58.05 | 0.5 | 12.7 | – | – | PLB | PLB | PLBE | PLB | |||
| 42.8 | 63.69 | 0.562 | 14.27 | – | – | PLB | PLB | PLB | PLB | |||
| 45.3 | 67.41 | 0.595 | 15.11 | – | – | PLB | PLB | PLB | PLB | |||
| 47.1 | 70.09 | 0.625 | 15.88 | – | – | PLB | PLB | PLB | PLB | |||
| 51.2 | 76.19 | 0.687 | 17.45 | – | – | – | – | – | – | |||
| 55.3 | 80.3 | 0.75 | 19.05 | – | – | – | – | – | – | |||
| 8 5/8 | 8.625 | 219.08 | 24 | 35.72 | 0.264 | 6.71 | – | PS | – | – | – | – |
| 28 | 41.62 | 0.304 | 7.72 | PS | – | – | – | – | – | |||
| 32 | 47.62 | 0.352 | 8.94 | PS | PSLB | – | – | – | – | |||
| 36 | 53.57 | 0.4 | 10.16 | – | PSLB | PLB | PLB | PLBE | PLB | |||
| 40 | 59.53 | 0.45 | 11.43 | – | – | PLB | PLB | PLBE | PLB | |||
| 44 | 65.48 | 0.5 | 12.7 | – | – | PLB | PLB | PLBE | PLB | |||
| 49 | 72.92 | 0.557 | 14.15 | – | – | PLB | PLB | PLBE | PLB | |||
| 9 5/8 | 9.625 | 244.48 | 32.3 | 48.07 | 0.312 | 7.92 | PS | – | – | – | – | – |
| 36 | 53.57 | 0.352 | 8.94 | PS | PSLB | – | – | – | – | |||
| 40 | 59.53 | 0.395 | 10.03 | – | PSLB | PLB | PLB | PLBE | – | |||
| 43.5 | 64.73 | 0.435 | 11.05 | – | – | PLB | PLB | PLBE | PLB | |||
| 47 | 69.94 | 0.472 | 11.99 | – | – | PLB | PLB | PLBE | PLB | |||
| 53.5 | 79.62 | 0.545 | 13.84 | – | – | PLB | PLB | PLBE | PLB | |||
| 58.4 | 86.91 | 0.595 | 15.11 | – | – | PLB | PLB | PLB | PLB | |||
| 59.4 | 88.4 | 0.609 | 15.47 | – | – | – | – | – | – | |||
| 64.9 | 96.58 | 0.672 | 17.07 | – | – | – | – | – | – | |||
| 70.3 | 104.62 | 0.734 | 18.64 | – | – | – | – | – | – | |||
| 75.6 | 112.5 | 0.797 | 20.24 | – | – | – | – | – | – | |||
| 10 3/4 | 10.75 | 273.05 | 32.75 | 48.74 | 0.279 | 7.09 | PS | – | – | – | – | – |
| 40.5 | 60.27 | 0.35 | 8.89 | PS | PSB | – | – | – | – | |||
| 15.5 | 67.71 | 0.4 | 10.16 | – | PSB | – | – | – | – | |||
| 51 | 75.9 | 0.45 | 11.43 | – | PSB | PSB | PSB | PSBE | PSB | |||
| 55.5 | 82.59 | 0.495 | 12.57 | – | – | PSB | PSB | PSBE | PSB | |||
| 60.7 | 90.33 | 0.545 | 13.84 | – | – | – | – | PSBE | PSB | |||
| 65.7 | 97.77 | 0.595 | 15.11 | – | – | – | – | PSB | PSB | |||
| 73.2 | 108.93 | 0.672 | 17.07 | – | – | – | – | – | – | |||
| 79.2 | 117.86 | 0.734 | 18.64 | – | – | – | – | – | – | |||
| 85.3 | 126.94 | 0.797 | 20.24 | – | – | – | – | – | – | |||
| 11 3/4 | 11.75 | 298.45 | 42 | 62.5 | 0.333 | 8.46 | PS | – | – | – | – | – |
| 47 | 69.94 | 0.375 | 20.24 | – | – | – | – | – | – | |||
| 54 | 80.36 | 0.435 | 8.46 | – | – | – | – | – | – | |||
| 60 | 89.29 | 0.489 | 9.53 | – | – | – | – | – | – | |||
| 65 | 96.73 | 0.534 | 11.05 | – | – | – | – | – | – | |||
| 71 | 105.66 | 0.582 | 14.42 | – | – | – | – | – | – | |||
| 13 3/8 | 13.375 | 339.73 | 48 | 71.43 | 0.33 | 8.38 | PS | – | – | – | – | – |
| 54.5 | 81.1 | 0.38 | 9.65 | – | PSB | – | – | – | – | |||
| 61 | 90.78 | 0.43 | 10.92 | – | PSB | – | – | – | – | |||
| 68 | 101.19 | 0.48 | 12.19 | – | PSB | PSB | PSB | PSB | PSB | |||
| 72 | 107.15 | 0.514 | 13.06 | – | – | PSB | PSB | PSB | PSB | |||
| 16 | 16 | 406.4 | 65 | 96.73 | 0.375 | 9.53 | PS | – | – | – | – | – |
| 75 | 111.61 | 0.438 | 11.13 | – | PSB | – | – | – | – | |||
| 84 | 125.01 | 0.495 | 12.57 | – | PSB | – | – | – | – | |||
| 109 | 162.21 | 0.656 | 16.66 | – | P | P | P | – | P | |||
| 18 5/8 | 18.625 | 473.08 | 87.5 | 130.21 | 0.435 | 11.05 | PS | PSB | – | – | – | – |
| 20 | 20 | 508 | 94 | 139.89 | 0.438 | 11.13 | PSL | PSLB | – | – | – | – |
| 106.5 | 158.49 | 0.5 | 12.7 | – | PSLB | – | – | – | – | |||
| 133 | 197.93 | 0.635 | 16.13 | – | PSLB | – | – | – | – | |||
| P--Plain;S--Short-thread;L--Long-thread;B--Buttress thread;E--Extreme thread | ||||||||||||
Length Range Table
API 5CT classifies pipe lengths into three "Ranges" to match rig derrick heights.
| Range Class | Tubing Length (ft / m) | Casing Length (ft / m) | Industry Convention |
| Range 1 (R1) | 20.0 - 24.0 (6.10 - 7.32) | 16.0 - 25.0 (4.88 - 7.62) | Rarely used |
| Range 2 (R2) | 28.0 - 32.0 (8.53 - 9.75) | 25.0 - 34.0 (7.62 - 10.36) | Most common standard |
| Range 3 (R3) | 38.0 - 45.0 (11.58 - 13.72) | 34.0 or more (10.36+) | For deep or ERD wells |
OCTG Casing and Tubing Steel Grades & Mechanical Properties
Steel grades determine the tensile strength, collapse resistance, and suitability for corrosive environments.
| Group | Common Grades | Min. Yield Strength (psi) | Service Environment |
| Group 1 | H40, J55, K55, N80 | 40k - 80k | General/Shallow wells, non-corrosive |
| Group 2 | L80, C90, T95, C110 | 80k - 110k | Sour Service (H2S) / Controlled Yield |
| Group 3 | P110 | 110k | Deep, high-pressure wells |
| Group 4 | Q125 | 125k | Extreme depth and pressure |
Caing and tubing Connection & Thread Types
This defines how the pipes are joined and their sealing capabilities.
| Pipe Type | Abbreviation | Full Description | Key Features |
| Tubing | NUE | Non-Upset | 10 Round threads (Obsolete/Rare) |
| EUE | External Upset | Forged upset ends (Standard/Strongest) | |
| IJ | Integral Joint | Flush connection for tight clearances | |
| Casing | STC | Short Round Thread | Short thread, 8-round (Low pressure) |
| LTC | Long Round Thread | Long thread, 8-round (Better tension) | |
| BTC | Buttress Thread | Trapezoidal thread (Industry standard) | |
| General | Premium | Gas-tight Connections | Non-API threads for gas-tight sealing |
API Casing and tubing Inspection & Testing (NDT):
Hydrostatic Test: Required for every joint to verify pressure integrity.
Drift Test: Ensures a standard-sized mandrel can pass through the pipe.
Non-Destructive Examination: Ultrasonic (UT), Magnetic Particle (MPI), or Eddy Current testing.
API Casing and tubing factory
oil country tubular goods test equipments
casing tubing certificate
GNEE OCTG Supply Range
Standard and Grades: API 5CT J55 / K55, N80-1, N80Q, C90, T95, P110, Q125 and 13Cr
Casing Pipe Size range: 5 1/2 "to 20" Length usually in R3.
Tubing Pipe dimensions range: 1.0 ", 1.315", 1.66 ", 1.9", 2.063 ", 2 3/8", 3 1/2 "and 4 1 /2", Length in R2.
Type of connections for Casing: BTC (thread coupling buttress), LTC (long round thread coupling), premium connection.
Types of connections for Tubing: BTC, NUE, EUE, Premium
FAQ
What is the API standard for casing?
The primary API standard for casing is API Spec 5CT (Specification for Casing and Tubing).
It is the industry-wide governing document that defines the technical requirements for dimensions, mechanical properties, steel grades, and testing methods for both casing and tubing used in oil and gas wells.
What is the API tolerance for casing?
According to API Spec 5CT, the standard manufacturing tolerances for casing are:
Outside Diameter (OD): +1.00% / -0.50% of the pipe's nominal OD.
Wall Thickness: The minimum wall thickness must not be more than 12.5% below the nominal wall thickness (there is no specified upper limit for wall thickness, provided weight requirements are met).
Weight: +6.5% / -3.5% per individual joint.
Straightness: Generally, the total deviation should not exceed 0.2% of the total pipe length.
What are the three common tubing sizes used?
The three most common API tubing sizes used in the oil and gas industry are: 2-3/8 inch (60.3 mm), 2-7/8 inch (73.0 mm), 3-1/2 inch (88.9 mm).
