Helmet Size Conversion Chart
To determine size, measure around head one inch above eyebrows and across largest portion of back of head
HJC Helmets
| Helmet Size | Hat Size | Head Circumference - Inches | Head Circumference - Metric |
| 2XS | 6 3/8 - 6 1/2 | 20- 20 1/2 | 51-52 |
| XS | 6 5/8 - 6 3/4 | 20 7/8 - 21 1/4 | 53-54 |
| S | 6 7/8 - 7 | 21 5/8 - 22 | 55-56 |
| M | 7 1/8 - 7 1/4 | 22 1/2 - 22 7/8 | 57-58 |
| L | 7 3/8 - 7 1/2 | 23 1/4 - 23 5/8 | 59-60 |
| XL | 7 5/8 - 7 3/4 | 24 - 24 3/8 | 61-62 |
| 2XL | 7 7/8 - 8 | 24 3/4 - 25 1/4 | 63-64 |
| 3XL | 8 1/8 - 8 1/4 | 25 5/8 - 26 | 65-66 |
Shoei Helmets
| Helmet Size | Hat Size | Head Circumference - Inches | Head Circumference - Metric |
| 2XS | 6 3/8 - 6 1/2 | 20 1/8 - 20 1/2 | 51-52 |
| XS | 6 5/8 - 6 3/4 | 20 7/8 - 21 1/4 | 53-54 |
| S | 6 7/8 - 7 | 21 5/8 - 22 | 55-56 |
| M | 7 1/8 - 7 1/4 | 22 1/2 - 22 7/8 | 57-58 |
| L | 7 3/8 - 7 1/2 | 23 1/4 - 23 5/8 | 59-60 |
| XL | 7 5/8 - 7 3/4 | 24 - 24 3/8 | 61-62 |
| 2XL | 7 7/8 - 8 | 24 3/4 - 25 1/4 | 63-64 |
| 3XL | 8 1/8 - 8 1/4 | 25 5/8 - 26 | 65-66 |
Nolan Helmets
| Helmet Size | Hat Size | Head Circumference - Inches | Head Circumference - Metric |
| 2XS | - |
- |
- |
| XS | 6 5/8 - 6 3/4 | 20 7/8 - 21 1/4 | 53-54 |
| S | 6 7/8 - 7 | 21 5/8 - 22 | 55-56 |
| M | 7 1/8 - 7 1/4 | 22 1/2 - 22 7/8 | 57-58 |
| L | 7 3/8 - 7 1/2 | 23 1/4 - 23 5/8 | 59-60 |
| XL | 7 5/8 - 7 3/4 | 24 - 24 1/2 | 61-62 |
| 2XL | 7 7/8 - 8 | 24 7/8 - 25 1/4 | 63-64 |
| 3XL | - |
- |
- |
