Home / Ring size chart / Size 8½
Ring size 8½ in mm and international sizes
A US/Canadian size 8½ ring is 18.5 mm across the inside and 58.2 mm around. This range covers many men's rings and larger women's sizes.
- US / Canada
- 8½
- UK / Australia
- Q½
- EU / ISO
- 58
- Japan / China
- 17
- India
- 18
- Italy / Spain / CH
- 18
- Inside diameter
- 18.5 mm
- Circumference
- 58.2 mm
- Diameter (in)
- 0.730″
Size 8½ and its neighbours
| US | UK | EU | Japan | Diameter | Circumference |
|---|---|---|---|---|---|
| 8 | P½ | 57 | 16 | 18.13 mm | 57.0 mm |
| 8¼ | Q | 58 | 16 | 18.34 mm | 57.6 mm |
| 8½ | Q½ | 58 | 17 | 18.54 mm | 58.2 mm |
| 8¾ | R | 59 | 17 | 18.74 mm | 58.9 mm |
| 9 | R½ | 60 | 18 | 18.95 mm | 59.5 mm |
Check it's really your size
A strip of paper wrapped around your finger should measure 57–59 mm for a size 8½. If you're buying a band 6 mm or wider, consider size 9 instead. Not sure? Try the ring size calculator or the online sizer.
Questions people ask
What is ring size 8½ in mm?
A US size 8½ ring has an inside diameter of 18.5 mm (0.730 in) and an inside circumference of 58.2 mm.
What is a US 8½ in UK and European sizes?
US 8½ is UK/Australian Q½ and EU (ISO) 58. In Italy, Spain and Switzerland it is 18.
What is a US 8½ in Japanese sizes?
The nearest Japanese and Chinese size is 17.
How do I know if I'm a size 8½?
Wrap a paper strip around your finger: if it measures about 58 mm, you're a 8½. Or measure a ring that fits: about 18.5 mm across the inside.