Jump Ring Size Guide: ID vs OD, Gauge (mm ↔ AWG), Typical Uses

What this guide covers

  • Difference between ID (inner diameter) and OD (outer diameter)

  • How wire diameter affects strength and clearance

  • Quick conversions: gauge ↔ mm

  • Typical sizes for common projects

 

ID vs OD (and why it matters)

  • OD = ID + 2 × wire diameter.

  • Use ID when you need to know the clearance (e.g., will a 3 mm chain link fit?).

  • Use OD when you need the overall footprint for spacing or aesthetics.

 

Fast picker (rules of thumb)

  • Clasps to chain: ID ≈ 1.5–2× chain wire diameter

  • Charm to bracelet: ID ≈ 4–6 mm, wire 0.8–1.0 mm (18–20 AWG)

  • Heavy pendants: wire ≥ 1.2 mm (≈16 AWG), ID 6–8 mm+

 

Gauge ↔ mm quick reference

AWG mm (wire) Typical use
22 0.64 Fine charms, delicate links
20 0.81 General purpose, light charms
18 1.02 Stronger general use
16 1.29 Heavy charms/pendants
14 1.63 Very heavy, high-strength needs

Tip: For open jump rings used in load-bearing joins (e.g., clasp points), prefer thicker wire or soldered/closed rings.

 

Typical sizes by project

Project Recommended ID Wire
Attach clasp to chain (fine) 3–4 mm 0.8–1.0 mm (20–18 AWG)
Standard bracelet charms 4–6 mm 0.8–1.0 mm
Pendant on necklace (medium chain) 5–7 mm 1.0–1.2 mm (18–16 AWG)
Heavy pendant / key charm 6–8 mm+ 1.2–1.6 mm

 

Conversion Calculators

Calculate outer diameter from inner diamter and wire diameter.

Calculate mm from AWG

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