Gauge Inches  Millimeters
20 - 0.8mm
18 - 1mm
16 - 1.2mm
14 - 1.6mm
12 - 2mm
10 - 2.4mm
8 - 3.2mm
6 - 4mm
4 - 5mm
2 - 6.5mm
- 8mm
00 - 10mm
- 7/16" 11mm
- 1/2" 12.5mm
- 9/16" 14mm
- 5/8" 16mm
- 3/4" 19mm
- 7/8" 22mm
- 1" 25mm
- 1-1/8" 28mm
- 1-1/4" 32mm
- 1-3/8" 35mm
-
1-1/2"
38mm
- 1-3/4" 44mm
- 1-7/8" 48mm
- 2" 51mm