International standard
ISO 3601-1 O-Ring Sizes
Verified nominal subset: size codes 001–026. This page is deliberately limited until the remaining ISO 3601 rows are independently checked.
Scope: This is a nominal dimensional reference. ISO 3601-1 also specifies tolerances and designation codes; the table below does not reproduce every tolerance class.
| ISO code | ID (mm) | CS (mm) | OD (mm) | ID (in) | CS (in) |
|---|---|---|---|---|---|
| ISO 001 | 0.74 | 1.02 | 2.78 | 0.0291 | 0.0402 |
| ISO 002 | 1.07 | 1.27 | 3.61 | 0.0421 | 0.0500 |
| ISO 003 | 1.42 | 1.52 | 4.46 | 0.0559 | 0.0598 |
| ISO 004 | 1.78 | 1.78 | 5.34 | 0.0701 | 0.0701 |
| ISO 005 | 2.57 | 1.78 | 6.13 | 0.1012 | 0.0701 |
| ISO 006 | 2.90 | 1.78 | 6.46 | 0.1142 | 0.0701 |
| ISO 007 | 3.68 | 1.78 | 7.24 | 0.1449 | 0.0701 |
| ISO 008 | 4.47 | 1.78 | 8.03 | 0.1760 | 0.0701 |
| ISO 009 | 5.28 | 1.78 | 8.84 | 0.2079 | 0.0701 |
| ISO 010 | 6.07 | 1.78 | 9.63 | 0.2390 | 0.0701 |
| ISO 011 | 7.65 | 1.78 | 11.21 | 0.3012 | 0.0701 |
| ISO 012 | 9.25 | 1.78 | 12.81 | 0.3642 | 0.0701 |
| ISO 013 | 10.82 | 1.78 | 14.38 | 0.4260 | 0.0701 |
| ISO 014 | 12.42 | 1.78 | 15.98 | 0.4890 | 0.0701 |
| ISO 015 | 14.00 | 1.78 | 17.56 | 0.5512 | 0.0701 |
| ISO 016 | 15.60 | 1.78 | 19.16 | 0.6142 | 0.0701 |
| ISO 017 | 17.17 | 1.78 | 20.73 | 0.6760 | 0.0701 |
| ISO 018 | 18.77 | 1.78 | 22.33 | 0.7390 | 0.0701 |
| ISO 019 | 20.35 | 1.78 | 23.91 | 0.8012 | 0.0701 |
| ISO 020 | 21.95 | 1.78 | 25.51 | 0.8642 | 0.0701 |
| ISO 021 | 23.52 | 1.78 | 27.08 | 0.9260 | 0.0701 |
| ISO 022 | 25.12 | 1.78 | 28.68 | 0.9890 | 0.0701 |
| ISO 023 | 26.70 | 1.78 | 30.26 | 1.0512 | 0.0701 |
| ISO 024 | 28.30 | 1.78 | 31.86 | 1.1142 | 0.0701 |
| ISO 025 | 29.87 | 1.78 | 33.43 | 1.1760 | 0.0701 |
| ISO 026 | 31.47 | 1.78 | 35.03 | 1.2390 | 0.0701 |
Current standard status
ISO lists ISO 3601-1:2012 as the current published edition, last reviewed and confirmed in 2022, with Amendment 1:2019.
Do not confuse conversion with equivalence
An AS568 dimension converted to millimetres is not automatically an ISO 3601 designation. Standard code, tolerance class and application requirements must be checked separately.
Cross-reference
Use the O-ring Cross Reference for dimensional comparison. Results are labelled as exact standard data or closest dimensional matches where supported.