JAMIKS single hat sizes 0 - 12 year
| Approximate age | Approximate head size (around) |
| 0-1 month | 36 cm |
| 1-2 month | 38 cm |
| 2-4 month | 40 cm |
| 4-6 month | 42 cm |
| 6-9 month | 44 cm |
| 9-12 month | 46 cm |
| 1-2 year | 48 cm |
| 2-4 year | 50 cm |
| 4-6 year | 52 cm |
| 8-10 year | 54 cm |
| 10-12 year | 56 cm |
JAMIKS dual hat sizes 9 month - 12 year
| Approximate age | Approximate head size (around) |
| 9-18 month | 46-48 |
| 2-5 year | 50-52 |
| 6-12 year | 54-56 |