US Size to UK Size
Convert US Size to UK Size with international size equivalence charts. Free online size converter.
Based on published international size equivalence charts. · Updated 2026-07-12
Ring Size Calculator
Ring Size Conversion Chart
| US | UK | EU | Japan |
|---|---|---|---|
| 3 | F | 44 | 1 |
| 3.25 | F½ | 44.5 | 2 |
| 3.5 | G | 45 | 3 |
| 3.75 | G½ | 45.5 | 4 |
| 4 | H | 46 | 5 |
| 4.25 | H½ | 46.5 | 6 |
| 4.5 | I | 47 | 7 |
| 4.75 | I½ | 47.5 | 8 |
| 5 | J | 48 | 9 |
| 5.25 | J½ | 48.5 | 10 |
| 5.5 | K | 49 | 11 |
| 5.75 | K½ | 49.5 | 12 |
| 6 | L | 50 | 13 |
| 6.25 | L½ | 50.5 | 14 |
| 6.5 | M | 51 | 15 |
| 6.75 | M½ | 51.5 | 16 |
| 7 | N | 52 | 17 |
| 7.25 | N½ | 52.5 | 18 |
| 7.5 | O | 53 | 19 |
| 7.75 | O½ | 53.5 | 20 |
| 8 | P | 54 | 21 |
| 8.25 | P½ | 54.5 | 22 |
| 8.5 | Q | 55 | 23 |
| 8.75 | Q½ | 55.5 | 24 |
| 9 | R | 56 | 25 |
| 9.25 | R½ | 56.5 | 26 |
| 9.5 | S | 57 | 27 |
| 9.75 | S½ | 57.5 | 28 |
| 10 | T | 58 | 29 |
| 10.25 | T½ | 58.5 | 30 |
| 10.5 | U | 59 | 31 |
| 10.75 | U½ | 59.5 | 32 |
| 11 | V | 60 | 33 |
| 11.25 | V½ | 60.5 | 34 |
| 11.5 | W | 61 | 35 |
| 11.75 | W½ | 61.5 | 36 |
| 12 | X | 62 | 37 |
The formula
Sizes map through equivalence charts, not a single multiplier. Use the chart above to find the matching size.