CONVERSION TABLE
To use this guide calculate the wall thickness of the tube by subtracting the Outside Diameter from the Inside Diameter and divide by 2. Then cross reference this on the table below to obtain the tube gauge.
GAUGE MM
5 5.38
6 4.87
7 4.47
8 4.06
9 3.65
10 3.25
11 2.95
12 2.64
13 2.34
14 2.03
15 1.83
16 1.63
17 1.42
18 1.22
19 1.02
20 0.91
 
FRACTION MM
1/8 3.17
3/16 4.76
1/4 6.35
5/16 7.94
3/8 9.52
7/16 11.1
1/2 12.70
5/8 15.88
3/4 19.05
7/8 22.23
1 25.40
1 1/16 27.0
1 1/8 28.6
1 1/4 31.75
1 11/32 34.1
1 3/8 34.92
1 1/2 38.1
1 3/4 44.4
2 50.8
2 3/8 60.3
2 1/2 63.5