Ring Size Conversion Chart
PRINTABLERing Size Conversion Table
| US/Canada | UK/Australia | EU | Diameter (mm) | Circumference (mm) |
|---|---|---|---|---|
| 3 | F | 44 | 14.1 | 44.2 |
| 3.5 | G | 45 | 14.5 | 45.5 |
| 4 | H | 46 | 14.9 | 46.8 |
| 4.5 | I | 47 | 15.3 | 48.0 |
| 5 | J | 49 | 15.7 | 49.3 |
| 5.5 | K | 50 | 16.1 | 50.6 |
| 6 | L | 51 | 16.5 | 51.9 |
| 6.5 | M | 52 | 16.9 | 53.1 |
| 7 | N | 54 | 17.3 | 54.4 |
| 7.5 | O | 55 | 17.7 | 55.7 |
| 8 | P | 56 | 18.1 | 57.0 |
| 8.5 | Q | 58 | 18.5 | 58.3 |
| 9 | R | 59 | 19.0 | 59.5 |
| 9.5 | S | 60 | 19.4 | 60.8 |
| 10 | T | 61 | 19.8 | 62.1 |
| 10.5 | U | 62 | 20.2 | 63.4 |
| 11 | V | 64 | 20.6 | 64.6 |
| 11.5 | W | 65 | 21.0 | 65.9 |
| 12 | X | 66 | 21.4 | 67.2 |
How to Measure Ring Size
To measure your ring size at home, wrap a string or paper strip around your finger, mark where it overlaps, and measure the length in millimeters. This is your circumference. Compare to the table above. For best results, measure when your hands are warm and at the end of the day when fingers are largest. For a printable ring sizer, use the print button below.
Reading the Conversion Table
Ring sizing is based on the inner circumference (or diameter) of the band measured in millimeters, which is why the mm columns are the most reliable reference. The US/Canada system uses a numeric scale that increases by about 0.4 mm in diameter per half size. The UK and Australia share a letter-based scale (A–Z, with half sizes), while most of continental Europe uses the ISO 8653 standard where the EU number equals the inner circumference in millimeters rounded to the nearest whole number. Because conversions are rounded, a given US size will not always map to exactly one EU number across every brand — treat the table as a close guide rather than a perfect equivalence, and when ordering, match the millimeter measurement when it is available.