Engineering Standards Tables
Quick reference for unit conversion and industrial standards
Diameter lookup (DN / NPS)
Enter DN in millimetres or NPS in inches; the matching table row is highlighted.
| DN (mm) | NPS (inch) | mm | inch |
|---|---|---|---|
| DN6 | 1/8" | 6 | 0.125 |
| DN8 | 1/4" | 8 | 0.25 |
| DN10 | 3/8" | 10 | 0.375 |
| DN15 | 1/2" | 15 | 0.5 |
| DN20 | 3/4" | 20 | 0.75 |
| DN25 | 1" | 25 | 1 |
| DN32 | 1-1/4" | 32 | 1.25 |
| DN40 | 1-1/2" | 40 | 1.5 |
| DN50 | 2" | 50 | 2 |
| DN65 | 2-1/2" | 65 | 2.5 |
| DN80 | 3" | 80 | 3 |
| DN90 | 3-1/2" | 90 | 3.5 |
| DN100 | 4" | 100 | 4 |
| DN125 | 5" | 125 | 5 |
| DN150 | 6" | 150 | 6 |
| DN200 | 8" | 200 | 8 |
| DN250 | 10" | 250 | 10 |
| DN300 | 12" | 300 | 12 |
| DN350 | 14" | 350 | 14 |
| DN400 | 16" | 400 | 16 |
| DN450 | 18" | 450 | 18 |
| DN500 | 20" | 500 | 20 |
| DN600 | 24" | 600 | 24 |
| DN650 | 26" | 650 | 26 |
| DN700 | 28" | 700 | 28 |
| DN750 | 30" | 750 | 30 |
| DN800 | 32" | 800 | 32 |
| DN850 | 34" | 850 | 34 |
| DN900 | 36" | 900 | 36 |