International Ring Size Converter
| GENERIC SIZE | CANADA and U.S. | DIAMETER (in millimeters) | U.K. | JAPAN | CIRCUMFERENCE ( in millimeters ) |
|---|---|---|---|---|---|
| 4 | 14.8mm | H 1/2 | 7 | 46.5mm | |
| 4 1/2 | 15.2mm | I 1/2 | 8 | 48mm | |
| XS | 5 | 15.6mm | J 1/2 | 9 | 49mm |
| 5 1/2 | 16mm | L | 10 | 50.5mm | |
| 6 | 16.4mm | M | 12 | 52mm | |
| S | 6 1/2 | 16.8mm | N | 13 | 53mm |
| 7 | 17.3mm | O | 14 | 54.5mm | |
| 7 1/2 | 17.7mm | P | 15 | 55.5mm | |
| M | 8 | 18.1mm | Q | 16 | 57mm |
| 8 1/2 | 18.5mm | Q 1/2 | 17 | 58mm | |
| 9 | 18.9mm | R 1/2 | 18 | 59.5mm | |
| L | 9 1/2 | 19.3mm | S 1/2 | 20 | 61mm |
| 10 | 19.7mm | T 1/2 | 21 | 62mm | |
| 10 1/2 | 20.1mm | U 1/2 | 22 | 63.5mm | |
| XL | 11 | 20.6mm | V 1/2 | 24 | 64.5mm |
| 11 1/2 | 21mm | W 1/2 | 25 | 66mm | |
| 12 | 21.4mm | Y | 26 | 67.5mm | |
| XXL | 12 1/2 | 21.8mm | Z | 27 | 68.5mm |
| 13 | 22.2mm | Z+1 | 28 | 70mm | |
| 13 1/2 | 22.6mm | Z+2 | 29 | 71mm | |
| XXXL | 14 | 23mm | Z+3 | 31 | 72.5mm |
| 14 1/2 | 23.4mm | Z+4 | 32 | 74mm | |
| 15 | 23.9mm | Z+5 | 33 | 75mm |