The most common O-ring sizes are based on the international standards listed below. The size range which is available in the greatest range of sizes, materials and hardness is the BS1806/AS568B.
| Standard | Description | Cross-sections |
| BS 1806 | British standard for inch series O-rings. This standard has the same development roots as the AS-568B standard, and it incorporates some additional sizes. | 1.02, 1.27, 1.53, 1.78, 2.62, 3.53, 5.34, 6.99 |
| SAE AS568B | American standard for O-rings. AS-568 is the Aerospace Standard (AS) as well as the SAE standard | 1.02, 1.27, 1.53, 1.78, 2.62, 3.53, 5.34, 6.99 |
| BS 4518 | British standard for metric series O-rings. BS 4518. | 1.6, 2.4, 3.0, 5.7, 8.4 |
| SMS 1586 | Swedish metric standard | 1.6, 2.4, 3.0, 5.7, 8.4 |
| DIN 3771-1 | German metric standard for fluid-sealing O-rings. | 1.80, 2.65, 3.55, 5.30, 7.00 |
| ISO 3601-1 | International standard for metric and inch series O-rings. The second edition includes the requirements for Aerospace (AS) applications. | 1.80, 2.65, 3.55, 5.30, 7.00 |
| JIS B2401 | Japanese industrial standard for metric series O-rings. This standard now includes the second edition of ISO 3601-1. | 1.90, 2.40, 3.10, 3.50, 5.70, 8.40 |
| NF T47-501 | French standard for O-rings. This standard is similar to the ISO 3601 and the DIN 3771 standards with some unique class designations. | 1.80, 2.65, 3.55, 5.30, 7.00 |