* Ring size conversion
US 4.5 ring size conversion
US 4.5 is an inside diameter of 15.3 mm (circumference 48 mm). In other systems that is US 4.5 = UK I = EU 48 = Japan 8.
Published July 11, 2026
US 4.5 — full conversion
- Inside diameter
- 15.3 mm
- Inside circumference
- 48 mm
- Japan
- 8
- US / Canada
- 4.5
- UK / Australia
- I
- EU (ISO)
- 48
Nearby sizes
- Ø 14.9 mm — US 4 = UK H = EU 47 = Japan 7
- Ø 15.7 mm — US 5 = UK J½ = EU 49 = Japan 9
Buying tips for US 4.5
- 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 US 4.5 in other ring size systems?
- A. US 4.5 converts to US 4.5 = UK I = EU 48 = Japan 8.
- Q. What is the diameter of US 4.5?
- A. Inside diameter 15.3 mm; inside circumference 48 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.
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