Size Conversion Table
| OD (mm) | DN or NB (mm) | Inches |
| 10.3 | 6 | 1/8 |
| 13.7 | 8 | 1/4 |
| 17.1 | 10 | 3/8 |
| 21.3 | 15 | 1/2 |
| 36.7 | 20 | 3/4 |
| 33.4 | 25 | 1 |
| 42.2 | 32 | 1 ¼ |
| 48.3 | 40 | 1 ½ |
| 60.3 | 50 | 2 |
| 76.1 | 65 | 2 ½ |
| 73.0 | 65 | 2 ½ API USA |
| 88.9 | 80 | 3 |
| 114.3 | 100 | 4 |
| 139.7 | 125 | 5 UK |
| 141.3 | 125 | 5 API USA |
| 165.1 | 150 | 6 |
| 168.3 | 150 | 6 API USA |
| 219.1 | 200 | 8 |
| 273.1 | 250 | 10 |
| 323.9 | 300 | 12 |
| 355.6 | 350 | 14 |
| 406.4 | 400 | 16 |
| 457.2 | 450 | 18 |
| 508.0 | 500 | 20 |
| 558.8 | 550 | 22 |
| 609.6 | 600 | 24 |
