Ring Size Converter
UK, US and EU ring size chart with diameter measurements.
Diameter—
Full Size Chart
| UK | US | EU | Diameter |
|---|---|---|---|
| A | ½ | 38 | 12.0mm |
| B | 1 | 39 | 12.4mm |
| C | 1½ | 40 | 12.7mm |
| D | 2 | 41 | 13.0mm |
| E | 2½ | 42 | 13.4mm |
| F | 3 | 43 | 13.7mm |
| G | 3½ | 44 | 14.0mm |
| H | 4 | 45 | 14.3mm |
| I | 4½ | 46 | 14.7mm |
| J | 5 | 47 | 15.0mm |
| K | 5½ | 48.5 | 15.3mm |
| L | 6 | 49 | 15.7mm |
| M | 6½ | 50 | 16.0mm |
| N | 7 | 51 | 16.3mm |
| O | 7½ | 52 | 16.7mm |
| P | 8 | 53 | 17.0mm |
| Q | 8½ | 54 | 17.3mm |
| R | 9 | 55 | 17.6mm |
| S | 9½ | 56 | 17.9mm |
| T | 10 | 57 | 18.2mm |
| U | 10½ | 58 | 18.6mm |
| V | 11 | 59 | 18.9mm |
| W | 11½ | 60 | 19.2mm |
| X | 12 | 61 | 19.5mm |
| Y | 12½ | 62 | 19.8mm |
| Z | 13 | 63 | 20.1mm |
How to measure ring size
The most accurate method is to use a ring sizer from a jeweller. Alternatively, measure the internal diameter of a ring that fits well using a ruler (in mm), then match it to the chart above.
UK vs US vs EU sizing
UK ring sizes use letters (A–Z). US sizes use numbers (½–13). EU sizes use the internal circumference in mm. Our chart above shows all three systems side by side.