international ring size conversion chart
includes both US and international sizes:
| Inside Diameter (MM) | USA/Canada | United Kingdom | France | Germany | Japan | Switzerland |
|---|---|---|---|---|---|---|
| 14.0 mm | 3 | F | 44 | 14 | 4 | 4 |
| 14.4 mm | 3½ | G | 45¼ | 14½ | 5½ | 6⅓ |
| 14.8 mm | 4 | H½ | 46½ | 15 | 7 | 6½ |
| 15.2 mm | 4½ | I½ | 47¾ | 15¼ | 8 | 8 |
| 15.6 mm | 5 | J½ | 49 | 15¾ | 9 | 9½ |
| 16.0 mm | 5½ | L | 50¾ | 16 | 10½ | 10¾ |
| 16.5 mm | 6 | M | 51½ | 16½ | 12 | 12¾ |
| 16.9 mm | 6½ | N | 52¾ | 17 | 13 | 14 |
| 17.3 mm | 7 | O | 54 | 17¼ | 14 | 15¼ |
| 17.7 mm | 7½ | P | 55¼ | 17¾ | 15 | 16½ |
| 18.2 mm | 8 | Q | 56¾ | 18 | 16 | 17¾ |
| 18.6 mm | 8½ | Q½ | 58 | 18½ | 17 | 18½ |
| 19.0 mm | 9 | R½ | 59¼ | 19 | 18 | 20 |
| 19.4 mm | 9½ | S½ | 60¾ | 19½ | 19 | 21 |
| 19.8 mm | 10 | T½ | 61¾ | 20 | 20 | 21¾ |
| 20.2 mm | 10½ | U½ | 62¾ | 20¼ | 22 | 22¾ |
| 20.6 mm | 11 | V½ | 64¼ | 20¾ | 23 | 24 |
| 21.0 mm | 11½ | W½ | 66 | 21 | 24 | 25¾ |
| 21.4 mm | 12 | Y | 67¼ | 21¼ | 25 | 27½ |
| 21.8 mm | 12½ | Z | 68 | 21¾ | 26 | 28¾ |
| 22.2 mm | 13 | Z + 1 | 69 | 22 | 27 | 29¼ |
This chart covers various international standards, including the United Kingdom, France, Germany, Japan, and Switzerland.