Giro Adults Helmet Sizing Chart
Adult Super Fit
| SM | MD | LG | XL |
| 51 - 55 cm | 55 - 59 cm | 59 - 63 cm | 61 - 65 cm |
Adult Full Face Super Fit
| SM | MD | LG | XL |
| 51 - 53 cm | 51 - 55 cm | 55 - 59 cm | 59 - 63 cm |
Adult Universal
| Model | Size (CM) |
| Women | 50 - 57 cm |
| Adult Unisex | 54 - 61 cm |
| Extra Large | 58 - 65 cm |
Youth Helmets
| Model | Size (CM) |
| Scamp XS | 45 - 49 cm |
| Scamp SM | 49 - 53 cm |
| Dime XS | 47 - 51 cm |
| Dime SM | 51 - 55 cm |
| Dime Universal | 50 - 57 cm |
| Tremor Youth | 50 - 57 cm |