As a hobbyist jewellery designer, I’ve found a constant struggle between measurements. Being taught in school the metric system, my parents would talk to me in terms of imperial because that is what they were taught when they were younger. Then once I went to school for goldsmithing and learned of gauges, this brought a whole new world of confusion to me. Even attempting to memorize the most commonly used gauges for jewellery making seemed to be a challenge. For those who would rather not memorize such an intense chart. I keep this chart beside my jewellery bench at all times.
This chart is for Gauge to Millimeter (mm)
Often it is the project that you’re working on that will determine the gauge of wire you’ll need.
For making your own earring posts and French hooks, the most comfortable gauge for an standard ear hole is.9mm which or 19g.
Crocheting wire is also becoming very popular, and a recommend gauge for type of project would be a 30g or a 28g.
A common confusion with gauges is that the lower the gauge number, the smaller the wire. This is not true, thicker gauges are actually lower numbers. For example a 10g is 2.5mm, and then for a thin wire example a 30g is a 0.25mm.
Be sure when you are buying your wire that you consider the gauge as well as the hardness, and these two factors can affect your jewellery design. If you are planning on giving it a texture by hammering the wire, make sure that the wire you choose will be thick enough to take on that forced texture and not become brittle and break. As it may not happen right away, it may happen later on in your jewellery designs while you’re twisting the wire around and when you least expect it, such a catastrophe is easy to stop buy getting a slightly thicker wire with a softer hardness.