Grass & Air Kids Footwear Size Guide
| UK | EU | US |
| Infant 3 | 19 | Infant 4 |
| Infant 4 | 21 | Infant 5 |
| Infant 5 | 22 | Infant 6 |
| Infant 6 | 23 | Infant 7 |
| Infant 7 | 24 | Infant 8 |
| Infant 8 | 25 | Infant 9 |
| Infant 9 | 27 | Infant 10 |
| Infant 10 | 28 | Infant 11 |
| Infant 11 | 29 | Infant 12 |
| Infant 12 | 30 | Infant 13 |
| Infant 13 | 31 | Junior 1 |
| Junior 1 | 32 | Junior 2 |
| Junior 2 | 34 | Junior 3 |
| Junior 3 | 36 | Junior 4 |
| Junior 4 | 37 | Junior 5 |
| Junior 5 | 38 | Junior 6 |
