Refrigeration Pipe Size Converter
Convert ACR copper pipe sizes between inches and millimetres. Includes a reference table of standard HVAC/R nominal pipe sizes.
Standard ACR / Refrigeration Copper Pipe Sizes
Source: BS EN 12735 / ASHRAE Handbook — nominal OD sizes for ACR tubing.
| Nominal size | OD (inches) | OD (mm) |
|---|---|---|
| 1/4" | 0.25" | 6.35 mm |
| 3/8" | 0.375" | 9.52 mm |
| 1/2" | 0.5" | 12.7 mm |
| 5/8" | 0.625" | 15.88 mm |
| 3/4" | 0.75" | 19.05 mm |
| 7/8" | 0.875" | 22.22 mm |
| 1 1/8" | 1.125" | 28.58 mm |
| 1 3/8" | 1.375" | 34.92 mm |
| 1 5/8" | 1.625" | 41.28 mm |
1 inch = 25.4 mm (exact, by international definition). Sizes shown are nominal OD. Wall thickness varies by type (K, L, ACR).