Since there are several common sizes of either filler material and consumable or non-consumable electrodes, here is a reference conversion table of imperial to metric. (Note, they're not perfect conversions, but how these values are typically used.)
| Fractions of inch (") | 1000ths of inch (") | Metric (mm) |
| 1/32 | 30/1000 | 0.8 |
| 40/1000 | 1.0 | |
| 3/64 | 45/1000 | 1.2 |
| 1/16 | 63/1000 | 1.6 |
| 5/64 | 80/1000 | 2.0 |
| 3/32 | 94/1000 | 2.4 |
| 1/8 | 125/1000 | 3.2 |
| 5/32 | 156/1000 | 4 |
| 13/64 | 200/1000 | 5 |
| 15/64 | 234/1000 | 6 |
Things to specify when ordering wire consumables:
Specification or classification of material.
Diameter of filler.
Length, for TIG rods, or spool size: D300 (12"), D200 (8"), D100 (4").
Amount of wire to be ordered, either in number of rods, spools or by weight.