* Ring size conversion
UK J½ ring size conversion
UK J½ is an inside diameter of 15.6 mm (circumference 49 mm). In other systems that is US 5 = UK J½ = EU 49 = Japan 8.
Published July 11, 2026
UK J½ — full conversion
- Inside diameter
- 15.6 mm
- Inside circumference
- 49 mm
- Japan
- 8
- US / Canada
- 5
- UK / Australia
- J½
- EU (ISO)
- 49
Nearby sizes
- Ø 15.2 mm — US 4.5 = UK I = EU 48 = Japan 7
- Ø 16 mm — US 5.5 = UK K½ = EU 50 = Japan 9
Buying tips for UK J½
- Wide bands feel tighter — consider going up ~½ US size for bands over 6 mm.
- Printable paper sizers are often ¼–½ size off; prefer a metal gauge at a jeweler.
- Selling the ring for gold? Check 18K ring melt value or the karat × weight calculator.
* Frequently asked
FAQ
- Q. What is UK J½ in other ring size systems?
- A. UK J½ converts to US 5 = UK J½ = EU 49 = Japan 8.
- Q. What is the diameter of UK J½?
- A. Inside diameter 15.6 mm; inside circumference 49 mm.
- Q. How should I measure my finger?
- A. Measure at the end of the day when fingers are warm. The ring must clear the knuckle; if knuckle and base differ, size for the knuckle and consider a comfort-fit band.
- Q. Can every ring be resized to this size?
- A. Most gold and platinum bands can move 1–2 sizes. Tension settings, eternity bands, and some titanium/tungsten rings cannot. See a jeweler before ordering a resize.
* Try it
Identify the jewelry in your hand, right now.
Just take a photo — AI reads the metal, gemstone, hallmark, era, and an estimated value range in seconds. First two scans free, no account required.
* Related