Gilbert's boot size conversion for junior UK sizes 12–5.5. UK 12 and 13 precede UK 1. The manufacturer does not list foot length.
| UK | US | EU |
| 12 | 13 | 30 |
| 13 | 1 | 31 |
| 1 | 2 | 32.5 |
| 1.5 | 2.5 | 33 |
| 2 | 2.5 | 34 |
| 2.5 | 3 | 35 |
| 3 | 3.5 | 35.5 |
| 3.5 | 4 | 36 |
| 4 | 4.5 | 37 |
| 4.5 | 5 | 37.5 |
| 5 | 5.5 | 38 |
| 5.5 | 6 | 38.5 |
Source: Gilbert boot size chart