Measure head circumference at widest point in inches. If you're between sizes, choose the smaller for a tighter fit or the larger for a looser fit.
| Head circumference in inches | Recommended size |
| 20 | 1 |
| 20.25 | 1 |
| 20.5 | 1 - 2 |
| 20.75 | 2 |
| 21 | 2 - 3 |
| 21.25 | 3 |
| 21.5 | 3 - 4 |
| 21.75 | 4 |
| 22 | 4 - 5 |
| 22.25 | 5 |
| 22.5 | 5 - 6 |
| 22.75 | 6 |
| 23 | 6 |