Free conversion chart
Ring size converter for US, UK, EU, and JP sizes.
Use this chart to compare common ring size systems. Shopify jewelry stores can use Ring Sizer Pro to bring these conversions into an interactive product-page sizing flow.
| US | UK | EU | JP | Diameter (mm) | Circumference (mm) |
|---|---|---|---|---|---|
| 4 | H | 47 | 7 | 14.9 | 46.8 |
| 5 | J 1/2 | 49 | 9 | 15.7 | 49.3 |
| 6 | L 1/2 | 52 | 12 | 16.5 | 51.9 |
| 7 | N 1/2 | 54 | 14 | 17.3 | 54.4 |
| 8 | P 1/2 | 57 | 16 | 18.1 | 57.0 |
| 9 | R 1/2 | 59 | 18 | 18.9 | 59.5 |
| 10 | T 1/2 | 62 | 20 | 19.8 | 62.1 |
| 11 | V 1/2 | 64 | 23 | 20.6 | 64.6 |
| 12 | Y | 67 | 25 | 21.4 | 67.2 |
| 13 | Z+1 | 70 | 27 | 22.2 | 69.7 |
How to use this chart
If you know a customer's inner ring diameter, match it to the nearest row. If you know circumference, use the circumference column. Rounded conversions differ slightly between jewelers, so show your own store policy next to any size recommendation.
For Shopify merchants
Static conversion charts help, but Ring Sizer Pro can guide shoppers through measurement and attempt to select the closest available Shopify size variant.
See Shopify App