This is a great resource for anyone planning or performing structured wiring installations. We have used this table in the past to make sure we size conduits appropriately for current need + room for expansion.
trade
size
inside
diam. inch
inside
diam. mm
cable
outside diameter mm (in)
3.3
(0.13)
4.6
(0.18)
5.6
(0.22)
6.1
(0.24)
7.4
(0.29)
7.9
(0.31)
9.4
(0.34)
13.5
(0.53)
15.8
(0.62)
17.8
(0.70)
1/2
.622
16
1
1
...