The interactive ISO 3601-1 O-ring size chart below lists preferred metric sizes by inside diameter (ID) and cross-section (CS). Outside diameter is calculated as ID + 2 × CS. Values are shown in millimeters by default — toggle to inches for US-spec comparison. Use the search box to filter by ID or cross-section.
| ID × CS (mm) | Inside Ø (mm)(in) | Outside Ø (mm)(in) | Cross-Section (mm)(in) |
|---|---|---|---|
| 5.8 × 1.6 | 5.800.228 | 9.000.354 | 1.600.063 |
| 7.7 × 1.6 | 7.700.303 | 10.900.429 | 1.600.063 |
| 9 × 1.6 | 9.000.354 | 12.200.480 | 1.600.063 |
| 11 × 1.6 | 11.000.433 | 14.200.559 | 1.600.063 |
| 13 × 1.6 | 13.000.512 | 16.200.638 | 1.600.063 |
| 14 × 1.6 | 14.000.551 | 17.200.677 | 1.600.063 |
| 15 × 1.6 | 15.000.591 | 18.200.717 | 1.600.063 |
| 16 × 1.6 | 16.000.630 | 19.200.756 | 1.600.063 |
| 18 × 1.6 | 18.000.709 | 21.200.835 | 1.600.063 |
| 19 × 1.6 | 19.000.748 | 22.200.874 | 1.600.063 |
| 20 × 1.6 | 20.000.787 | 23.200.913 | 1.600.063 |
| 22.4 × 1.6 | 22.400.882 | 25.601.008 | 1.600.063 |
| 25 × 1.6 | 25.000.984 | 28.201.110 | 1.600.063 |
| 28 × 1.6 | 28.001.102 | 31.201.228 | 1.600.063 |
| 30 × 1.6 | 30.001.181 | 33.201.307 | 1.600.063 |
| 31.5 × 1.6 | 31.501.240 | 34.701.366 | 1.600.063 |
| 35.5 × 1.6 | 35.501.398 | 38.701.524 | 1.600.063 |
| 40 × 1.6 | 40.001.575 | 43.201.701 | 1.600.063 |
| 45 × 1.6 | 45.001.772 | 48.201.898 | 1.600.063 |
| 50 × 1.6 | 50.001.969 | 53.202.094 | 1.600.063 |
| 8 × 2 | 8.000.315 | 12.000.472 | 2.000.079 |
| 10 × 2 | 10.000.394 | 14.000.551 | 2.000.079 |
| 11.4 × 2 | 11.400.449 | 15.400.606 | 2.000.079 |
| 12.5 × 2 | 12.500.492 | 16.500.650 | 2.000.079 |
| 14 × 2 | 14.000.551 | 18.000.709 | 2.000.079 |
| 15 × 2 | 15.000.591 | 19.000.748 | 2.000.079 |
| 16 × 2 | 16.000.630 | 20.000.787 | 2.000.079 |
| 18 × 2 | 18.000.709 | 22.000.866 | 2.000.079 |
| 20 × 2 | 20.000.787 | 24.000.945 | 2.000.079 |
| 22.4 × 2 | 22.400.882 | 26.401.039 | 2.000.079 |
| 25 × 2 | 25.000.984 | 29.001.142 | 2.000.079 |
| 28 × 2 | 28.001.102 | 32.001.260 | 2.000.079 |
| 30 × 2 | 30.001.181 | 34.001.339 | 2.000.079 |
| 31.5 × 2 | 31.501.240 | 35.501.398 | 2.000.079 |
| 35.5 × 2 | 35.501.398 | 39.501.555 | 2.000.079 |
| 40 × 2 | 40.001.575 | 44.001.732 | 2.000.079 |
| 45 × 2 | 45.001.772 | 49.001.929 | 2.000.079 |
| 50 × 2 | 50.001.969 | 54.002.126 | 2.000.079 |
| 56 × 2 | 56.002.205 | 60.002.362 | 2.000.079 |
| 63 × 2 | 63.002.480 | 67.002.638 | 2.000.079 |
| 10 × 2.4 | 10.000.394 | 14.800.583 | 2.400.094 |
| 12 × 2.4 | 12.000.472 | 16.800.661 | 2.400.094 |
| 14 × 2.4 | 14.000.551 | 18.800.740 | 2.400.094 |
| 15 × 2.4 | 15.000.591 | 19.800.780 | 2.400.094 |
| 16 × 2.4 | 16.000.630 | 20.800.819 | 2.400.094 |
| 18 × 2.4 | 18.000.709 | 22.800.898 | 2.400.094 |
| 20 × 2.4 | 20.000.787 | 24.800.976 | 2.400.094 |
| 22.4 × 2.4 | 22.400.882 | 27.201.071 | 2.400.094 |
| 25 × 2.4 | 25.000.984 | 29.801.173 | 2.400.094 |
| 28 × 2.4 | 28.001.102 | 32.801.291 | 2.400.094 |
| 30 × 2.4 | 30.001.181 | 34.801.370 | 2.400.094 |
| 31.5 × 2.4 | 31.501.240 | 36.301.429 | 2.400.094 |
| 35.5 × 2.4 | 35.501.398 | 40.301.587 | 2.400.094 |
| 40 × 2.4 | 40.001.575 | 44.801.764 | 2.400.094 |
| 45 × 2.4 | 45.001.772 | 49.801.961 | 2.400.094 |
| 50 × 2.4 | 50.001.969 | 54.802.157 | 2.400.094 |
| 56 × 2.4 | 56.002.205 | 60.802.394 | 2.400.094 |
| 63 × 2.4 | 63.002.480 | 67.802.669 | 2.400.094 |
| 71 × 2.4 | 71.002.795 | 75.802.984 | 2.400.094 |
| 80 × 2.4 | 80.003.150 | 84.803.339 | 2.400.094 |
| 14 × 3 | 14.000.551 | 20.000.787 | 3.000.118 |
| 16 × 3 | 16.000.630 | 22.000.866 | 3.000.118 |
| 18 × 3 | 18.000.709 | 24.000.945 | 3.000.118 |
| 20 × 3 | 20.000.787 | 26.001.024 | 3.000.118 |
| 22.4 × 3 | 22.400.882 | 28.401.118 | 3.000.118 |
| 25 × 3 | 25.000.984 | 31.001.220 | 3.000.118 |
| 28 × 3 | 28.001.102 | 34.001.339 | 3.000.118 |
| 30 × 3 | 30.001.181 | 36.001.417 | 3.000.118 |
| 31.5 × 3 | 31.501.240 | 37.501.476 | 3.000.118 |
| 35.5 × 3 | 35.501.398 | 41.501.634 | 3.000.118 |
| 40 × 3 | 40.001.575 | 46.001.811 | 3.000.118 |
| 45 × 3 | 45.001.772 | 51.002.008 | 3.000.118 |
| 50 × 3 | 50.001.969 | 56.002.205 | 3.000.118 |
| 56 × 3 | 56.002.205 | 62.002.441 | 3.000.118 |
| 63 × 3 | 63.002.480 | 69.002.717 | 3.000.118 |
| 71 × 3 | 71.002.795 | 77.003.031 | 3.000.118 |
| 80 × 3 | 80.003.150 | 86.003.386 | 3.000.118 |
| 90 × 3 | 90.003.543 | 96.003.780 | 3.000.118 |
| 100 × 3 | 100.003.937 | 106.004.173 | 3.000.118 |
| 18 × 3.5 | 18.000.709 | 25.000.984 | 3.500.138 |
| 20 × 3.5 | 20.000.787 | 27.001.063 | 3.500.138 |
| 22.4 × 3.5 | 22.400.882 | 29.401.157 | 3.500.138 |
| 25 × 3.5 | 25.000.984 | 32.001.260 | 3.500.138 |
| 28 × 3.5 | 28.001.102 | 35.001.378 | 3.500.138 |
| 30 × 3.5 | 30.001.181 | 37.001.457 | 3.500.138 |
| 31.5 × 3.5 | 31.501.240 | 38.501.516 | 3.500.138 |
| 35.5 × 3.5 | 35.501.398 | 42.501.673 | 3.500.138 |
| 40 × 3.5 | 40.001.575 | 47.001.850 | 3.500.138 |
| 45 × 3.5 | 45.001.772 | 52.002.047 | 3.500.138 |
| 50 × 3.5 | 50.001.969 | 57.002.244 | 3.500.138 |
| 56 × 3.5 | 56.002.205 | 63.002.480 | 3.500.138 |
| 63 × 3.5 | 63.002.480 | 70.002.756 | 3.500.138 |
| 71 × 3.5 | 71.002.795 | 78.003.071 | 3.500.138 |
| 80 × 3.5 | 80.003.150 | 87.003.425 | 3.500.138 |
| 20 × 5.7 | 20.000.787 | 31.401.236 | 5.700.224 |
| 25 × 5.7 | 25.000.984 | 36.401.433 | 5.700.224 |
| 28 × 5.7 | 28.001.102 | 39.401.551 | 5.700.224 |
| 30 × 5.7 | 30.001.181 | 41.401.630 | 5.700.224 |
| 31.5 × 5.7 | 31.501.240 | 42.901.689 | 5.700.224 |
| 35.5 × 5.7 | 35.501.398 | 46.901.846 | 5.700.224 |
| 40 × 5.7 | 40.001.575 | 51.402.024 | 5.700.224 |
| 45 × 5.7 | 45.001.772 | 56.402.220 | 5.700.224 |
| 50 × 5.7 | 50.001.969 | 61.402.417 | 5.700.224 |
| 56 × 5.7 | 56.002.205 | 67.402.654 | 5.700.224 |
| 63 × 5.7 | 63.002.480 | 74.402.929 | 5.700.224 |
| 71 × 5.7 | 71.002.795 | 82.403.244 | 5.700.224 |
| 80 × 5.7 | 80.003.150 | 91.403.598 | 5.700.224 |
| 90 × 5.7 | 90.003.543 | 101.403.992 | 5.700.224 |
| 100 × 5.7 | 100.003.937 | 111.404.386 | 5.700.224 |
| 40 × 8 | 40.001.575 | 56.002.205 | 8.000.315 |
| 50 × 8 | 50.001.969 | 66.002.598 | 8.000.315 |
| 56 × 8 | 56.002.205 | 72.002.835 | 8.000.315 |
| 63 × 8 | 63.002.480 | 79.003.110 | 8.000.315 |
| 71 × 8 | 71.002.795 | 87.003.425 | 8.000.315 |
| 80 × 8 | 80.003.150 | 96.003.780 | 8.000.315 |
| 90 × 8 | 90.003.543 | 106.004.173 | 8.000.315 |
| 100 × 8 | 100.003.937 | 116.004.567 | 8.000.315 |
Reference metric O-ring sizes on your own engineering resources page? Copy the code below and paste it into your HTML — it loads a live, filterable ISO 3601 chart that stays in sync with the standard.
Related: AS568 O-Ring Size Chart Tool · JIS B2401 O-Ring Size Chart Tool.
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