See Nooks Designs full size guide here
| Size | Age | |
| 2.5 | 0-6 months | |
| 4 | 6-12 months | |
| 5.5 | 12-18 months | |
| 7 | 8-24 months | |
| 8.5 | 2-3 years | |
| 10 | 3-4 years |