Home / Ring size chart / Size 3½
Ring size 3½ in mm and international sizes
A US/Canadian size 3½ ring is 14.5 mm across the inside and 45.5 mm around. This is on the smaller side of adult sizes and common for little fingers, slim fingers and midi rings.
- US / Canada
- 3½
- UK / Australia
- G½
- EU / ISO
- 45
- Japan / China
- 5
- India
- 5
- Italy / Spain / CH
- 5
- Inside diameter
- 14.5 mm
- Circumference
- 45.5 mm
- Diameter (in)
- 0.570″
Size 3½ and its neighbours
| US | UK | EU | Japan | Diameter | Circumference |
|---|---|---|---|---|---|
| 3 | F½ | 44 | 4 | 14.07 mm | 44.2 mm |
| 3¼ | G | 45 | 5 | 14.27 mm | 44.8 mm |
| 3½ | G½ | 45 | 5 | 14.47 mm | 45.5 mm |
| 3¾ | H | 46 | 6 | 14.68 mm | 46.1 mm |
| 4 | H½ | 47 | 7 | 14.88 mm | 46.8 mm |
Check it's really your size
A strip of paper wrapped around your finger should measure 44–47 mm for a size 3½. If you're buying a band 6 mm or wider, consider size 4 instead. Not sure? Try the ring size calculator or the online sizer.
Questions people ask
What is ring size 3½ in mm?
A US size 3½ ring has an inside diameter of 14.5 mm (0.570 in) and an inside circumference of 45.5 mm.
What is a US 3½ in UK and European sizes?
US 3½ is UK/Australian G½ and EU (ISO) 45. In Italy, Spain and Switzerland it is 5.
What is a US 3½ in Japanese sizes?
The nearest Japanese and Chinese size is 5.
How do I know if I'm a size 3½?
Wrap a paper strip around your finger: if it measures about 45 mm, you're a 3½. Or measure a ring that fits: about 14.5 mm across the inside.