Here is a size chart for your convenience.
| USA size | Dia. inch | Dia. mm | Circ. mm | British size | French size | German size | Japanese size | Swiss size |
| 0000 | .390 | 9.91 | 31.1 | |||||
| 00 | .422 | 10.72 | 33.7 | |||||
| 0 | .454 | 11.53 | 36.2 | |||||
| 1/2 | .474 | 11.95 | 37.5 | A | ||||
| 3/4 | .482 | 12.18 | 38.3 | A 1/2 | ||||
| 1 | .487 | 12.37 | 38.9 | B | 1 | |||
| 1 1/4 | 12.60 | 39.6 | B 1/2 | |||||
| 1 1/2 | .503 | 12.78 | 40.2 | C | ||||
| 1 3/4 | 13.00 | 40.8 | C 1/2 | |||||
| 2 | .520 | 13.21 | 41.5 | D | 41 1/2 | 13 1/2 | 2 | 1 1/2 |
| 2 1/4 | 13.41 | 42.1 | D 1/2 | |||||
| 2 1/2 | .536 | 13.61 | 42.7 | E | 42 3/4 | 13 3/4 | 3 | 2 3/4 |
| 2 3/4 | 13.83 | 43.4 | E 1/2 | |||||
| 3 | .553 | 14.05 | 44.0 | F | 44 | 14 | 4 | 4 |
| 3 1/8 | 14.15 | 44.3 | F 1/2 | |||||
| 3 1/4 | 14.25 | 44.6 | ||||||
| 3 3/8 | 14.36 | 44.9 | G | 45 1/4 | 5 | 5 1/4 | ||
| 3 1/2 | .569 | 14.45 | 45.2 | 14 1/2 | ||||
| 3 5/8 | 14.56 | 45.6 | G 1/2 | 6 | ||||
| 3 3/4 | 14.65 | 45.9 | H | 46 1/2 | 6 1/2 | |||
| 4 | .585 | 14.86 | 46.5 | H 1/2 | 15 | 7 | ||
| 4 1/4 | 15.04 | 47.1 | I | 47 3/4 | 7 3/4 | |||
| 4 1/2 | .601 | 15.27 | 47.8 | I 1/2 | 15 1/4 | 8 | ||
| 4 5/8 | 15.40 | 48.1 | J | 49 | 15 1/2 | 9 | ||
| 4 3/4 | 15.53 | 48.4 | ||||||
| 5 | .618 | 15.70 | 49.0 | J 1/2 | 15 3/4 | 9 | ||
| 5 1/8 | 15.80 | 49.3 | K | 50 | 10 | |||
| 5 1/4 | 15.90 | 49.6 | ||||||
| 5 3/8 | 16.0 | 50.0 | K 1/2 | 10 | ||||
| 5 1/2 | .634 | 16.10 | 50.3 | L | 51 3/4 | 16 | 11 3/4 | |
| 5 3/4 | 16.30 | 50.9 | ||||||
| 5 7/8 | 16.41 | 51.3 | L 1/2 | |||||
| 6 | .650 | 16.51 | 51.5 | M | 52 3/4 | 16 1/2 | 12 | 12 3/4 |
| 6 1/4 | 16.71 | 52.2 | M 1/2 | |||||
| 6 1/2 | .666 | 16.92 | 52.8 | N | 54 | 17 | 13 | 14 |
| 6 3/4 | 17.13 | 53.4 | N 1/2 | |||||
| 7 | .683 | 17.35 | 54.0 | O | 55 1/4 | 17 1/4 | 14 | 15 1/4 |
| 7 1/4 | 17.45 | 54.7 | O 1/2 | |||||
| 7 1/2 | .699 | 17.75 | 55.3 | P | 56 1/2 | 17 3/4 | 15 | 16 1/2 |
| 7 3/4 | 17.97 | 55.9 | P 1/2 | |||||
| 8 | .716 | 18.19 | 56.6 | Q | 57 3/4 | 18 | 16 | 17 3/4 |
| 8 1/4 | 18.35 | 57.2 | Q 1/2 | |||||
| 8 1/2 | .732 | 18.53 | 57.8 | 18 1/2 | 17 | |||
| 8 5/8 | 18.61 | 58.4 | R | 59 | 19 | |||
| 8 3/4 | 18.69 | 58.4 | ||||||
| 8 7/8 | 18.80 | 59.0 | R 1/2 | |||||
| 9 | .748 | 18.89 | 59.1 | 19 | 18 | |||
| 9 1/8 | 19.10 | 59.4 | S | 60 1/4 | 20 1/4 | |||
| 9 1/4 | 19.22 | 59.7 | ||||||
| 9 3/8 | 19.31 | 60.0 | S 1/2 | |||||
| 9 1/2 | .764 | 19.41 | 60.3 | 19 1/2 | 19 | |||
| 9 5/8 | 19.51 | 60.6 | T | 61 1/2 | 21 1/2 | |||
| 9 3/4 | 19.62 | 60.9 | ||||||
| 10 | .781 | 19.84 | 61.6 | T 1/2 | 20 | 20 | ||
| 10 1/4 | 20.02 | 62.2 | U | 62 3/4 | 21 | 22 3/4 | ||
| 10 1/2 | .797 | 20.20 | 62.8 | U 1/2 | 20 1/4 | 22 | ||
| 10 5/8 | 20.32 | 63.1 | V | 63 | 23 3/4 | |||
| 10 3/4 | 20.44 | 63.5 | ||||||
| 11 | .814 | 20.68 | 64.1 | V 1/2 | 20 3/4 | 23 | ||
| 11 1/8 | 20.76 | 64.3 | W | 65 | 25 | |||
| 11 1/4 | 20.85 | 64.7 | ||||||
| 11 3/8 | 20.94 | 65.0 | W 1/2 | |||||
| 11 1/2 | 21.08 | 65.3 | 21 | 24 | ||||
| 11 5/8 | .830 | 21.18 | 65.7 | X | 66 1/4 | 26 1/4 | ||
| 11 3/4 | 21.24 | 66.0 | ||||||
| 11 7/8 | 21.30 | 66.3 | X 1/2 | |||||
| 12 | .846 | 21.49 | 66.6 | Y | 67 1/2 | 21 1/4 | 25 | 27 1/2 |
| 12 1/4 | 21.69 | 67.2 | Y 1/2 | |||||
| 12 1/2 | .862 | 21.89 | 67.9 | Z | 68 3/4 | 21 3/4 | 26 | 28 3/4 |
| 12 3/4 | 22.10 | 68.5 | Z 1/2 | |||||
| 13 | .879 | 22.33 | 69.1 | 22 | 27 |