Jump Ring Sizes & Gauges: A Quick Reference

The three measurements

Every jump ring is described by the same three numbers. Once you can read them, you can order the right ring the first time.

  • Inner diameter (ID): the usable space inside the ring, in millimetres. This is the number that decides what fits through it.
  • Wire thickness (gauge): the thickness of the wire the ring is made from. Thicker wire = a stronger, chunkier ring.
  • Outer diameter (OD): ID plus twice the wire thickness. If a ring is 4mm ID in 1mm wire, its OD is 6mm.

Gauge, in plain terms

Gauge runs backwards: the bigger the number, the thinner the wire. The sizes you'll meet most often in jewelry work:

  • 18 gauge ≈ 1.0mm wire — sturdy; good for clasps and key load-bearing joins.
  • 20 gauge ≈ 0.8mm wire — the everyday all-rounder for charms and connectors.
  • 22 gauge ≈ 0.65mm wire — delicate; fine chains and light charms.

Picking a ring for the job

  • Attaching a light charm: a small ID in 20–22 gauge — just big enough to pass through the charm's loop and the chain.
  • Joining a clasp: step up to 18–20 gauge; this join takes the strain every time the piece is worn.
  • Permanent jewelry welds: match the wire to your chain so the welded ring closes flush and holds.
  • Anything heavy or long: consider a split ring (it works like a tiny key ring and can't twist open) or a closed, soldered ring instead of a standard open ring.

A useful rule of thumb: the ring should be only just big enough for the job. Oversized rings look clumsy and catch; undersized rings won't close without distorting.

Open, close, done properly

Never pull a jump ring apart sideways like a bagel — that warps it for good. Hold each side with flat or chain-nose pliers and twist one side toward you and the other away, like opening a door. To close, twist back past centre a fraction, then settle the ends together; a properly closed ring gives a tiny click and shows no gap when you run a fingernail over the join.

Where ours live

Our jump rings, split rings and the rest of the hardware are in Clasps & Findings, in 18K gold filled and stainless steel PVD to match your chains. Not sure which size your project needs? Email us at support@gemsdirectsusa.com — a real person answers.