# Jump Ring Measurements

Some patterns call for jump rings measured in OD, some in ID. And many suppliers don't label every jump ring with the Outer Diameter, Inner Diameter, and Wire Gauge. If you know either the ID or the OD as well as the gauge, you can find your missing measurement.
Instructions
Jump rings are typically measured by their Inner Diameter, Outer diameter, and wire gauge. For example, if you made your own jump rings from 18-gauge wire around a 5mm dowel, the Inner Diameter is 5mm, the gauge is 18-gauge (or 1.02mm, found in the Wire Conversion Chart). But what's the outer diameter?
To find the Inner Diameter (ID)
Inner Diameter = OD - (wire gauge * 2)
To find the Outer Diameter (OD)

Outer Diameter = ID + (wire gauge * 2)

So using the example of an 18-gauge jump ring made around a 5mm dowel, remembering that 18-gauge is 1.02 mm:

OD = 5 + (1.02*2)

OD = 5 + 2.04

OD = 7.04mm for an 18-gauge jump ring with a 5mm ID.

### Materials

Jump Rings found by metal type

### Tools

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• Category: General Education
• Technique(s): Chain Making, Making Findings, Making Jump Rings, General Education