| US | EU | UK | Mexico | Inches | Centimeters |
| 5 | 36.5 | 4.5 | 4 | 9 | 22.9 |
| 5.5 | 37 | 5 | 4.5 | 9 1/8 | 23.2 |
| 6 | 37.5 | 5.5 | 5 | 9 1/4 | 23.5 |
| 6.5 | 38 | 6 | 5.5 | 9 1/2 | 24.1 |
| 7 | 38.5 | 6.5 | 6 | 9 5/8 | 24.4 |
| 7.5 | 39 | 7 | 6.5 | 9 3/4 | 24.8 |
| 8 | 39.5 | 7.5 | 7 | 10 | 25.4 |
| 8.5 | 40 | 8 | 7.5 | 10 1/8 | 25.7 |
| 9 | 41 | 8.5 | 8 | 10 1/4 | 26 |
| 9.5 | 42 | 9 | 8.5 | 10 1/2 | 26.7 |
| 10 | 43 | 9.5 | 9 | 10 5/8 | 27 |
| 10.5 | 44 | 10 | 9.5 | 10 3/4 | 27.3 |
| 11 | 45 | 10.5 | 10 | 11 | 27.9 |
| 12 | 46 | 11.5 | 11 | 11 1/4 | 28.6 |
| 13 | 47 | 12.5 | 12 | 11 5/8 | 29.5 |
| 14 | 48 | 13.5 | 13 | 12 | 30.5 |
| 15 | 49 | 14.5 | 14 | 12 1/4 | 31.1 |
| 16 | 50 | 15.5 | 15 | 12 5/8 | 32.1 |
| 17 | 51 | 16.5 | 16 | 13 | 33 |
| 18 | 52 | 17.5 | 17 | 13 1/4 | 33.7 |
| 19 | 53 | 18.5 | 18 | 13 5/8 | 34.6 |
| 20 | 54 | 19.5 | 19 | 14 | 35.6 |
| Narrow | 3A, AAA, 2A, AA, B, N, C, S |
| Medium | D, M |
| Wide | E, W, 2E, EE |
| Extra Wide | WW, XS, 3E, EEE, 4E, EEEE |