Size Charts for Giro Helmets
Adult Helmets
| Helmet Sizing | Inches | Centimeters |
| Small | 20.50 - 21.75" | 52 - 55.5 cm |
| Medium | 21.75 - 23" | 55.5 - 59 cm |
| Large | 23 - 24.25" | 59 - 62.5 cm |
| X-Large | 24.50 - 25.50" | 62.5 - 65 cm |
Kid's Helmets
| Helmet Size | Inches | Centimeters |
| Extra Small | 19.25 - 20.50" | 48.5 - 52 cm |
| Small | 20.50 - 21.75" | 52 - 55.5 cm |
| Medium | 21.75 - 23" | 55.5 - 59 cm |