Wire Gauge Chart: SWG & BWG to mm Conversion
25 September 20261 min read
A wire gauge to millimetre conversion chart. SWG and BWG gauge sizes in mm for binding wire and baling wire, with an explanation of how the gauge system works.
In export trade, wire diameter is usually specified by gauge. There are two common systems: SWG (Standard Wire Gauge, used in the UK) and BWG (Birmingham Wire Gauge, common for baling wire). The higher the gauge number, the thinner the wire.
SWG to mm chart (binding wire / tie wire)
| SWG | mm |
|---|---|
| 8 | 4.06 |
| 10 | 3.25 |
| 12 | 2.64 |
| 14 | 2.03 |
| 16 | 1.63 |
| 18 | 1.22 |
| 20 | 0.91 |
BWG to mm chart (baling wire)
| BWG | mm |
|---|---|
| 8 | 4.19 |
| 10 | 3.40 |
| 11 | 3.05 |
| 12 | 2.77 |
| 14 | 2.11 |
| 16 | 1.65 |
Frequently asked questions
What is 16 gauge wire in mm?
16 SWG is about 1.63 mm; 16 BWG is about 1.65 mm. The two systems are close but not identical.
What is 18 gauge binding wire in mm?
18 SWG is approximately 1.22 mm, a common size for light rebar binding.
Does higher gauge mean thicker wire?
No — higher gauge means thinner wire. For example, 20 gauge is thinner than 14 gauge.
AFA Çelik produces wire from 1.00-6.00 mm in the gauge you require. Request a quote or contact us.
