Helmet Size & Conversion charts by brand

One important factor to consider when choosing a Motorcycle helmet to buy, is that not all manufacturers use the same sizing guides. You’ll need to know the differences in order to choose the right helmet size to fit you – this is especially important if you are buying a brand that you may not have worn before.

To help, we have pulled together a motorcycle helmet sizing guide, and size conversion charts for each of the main motorcycle helmet manufacturers.

AGV Helmet Size Chart

This AGV Helmet Size Conversion Chart will help you to determine what AGV helmet size will provide you with the best fit.

  • Measure your head size. Pass a tape measure horizontally around your head at a height of about one inch (2.5cm) above your eyebrows. This will measure the largest portion of your head.
  • Select the helmet that is closest to your head size. Often times your head measurement may fall between two helmet sizes. When this occurs you should first try on the smaller size.
  • Helmet should have a snug fit around your head yet remain comfortable for long riding periods
  • Note: Sizing charts should be used only as a guide.
Size Centimeter Inches Hat Size
XXS 51 20 1/8 6 3/8
XS 53 20 7/8 6 5/8
S 55 21 5/8 6 7/8
M 57 22 3/8 7 1/8
L 60 23 1/2 7 1/2
XL 62 24 3/8 7 3/4
2XL 63 24 3/4 7 7/8

Arai Helmet Size Chart

This chart shows the helmet size conversion guide that Arai helmets use. This will allow you to measure your head and identify what size Arai helmet that you’ll need for the best fit.

ARAI HELMET SIZE CONVERSION CHART
Inches Hat Size Metric Equals
21-1/4 6-3/4 54 Small
21-5/8 6-7/8 55 Small
22 7 56 Medium
22-3/8 7-1/8 57 Medium
22-3/4 7-1/4 58 Large
23-1/8 7-3/8 59 Large
23-1/2 7-1/2 60 X-Large
23-7/8 7-5/8 61 X-Large
24-1/4 7-3/4 62 XX-Large

HJC Helmet Size Chart

This HJC Helmet Size chart will help you determine what size HJC helmet will suit you best.

HJC Helmet Size Conversion Chart
Size
Centimeter
Hat Size
Inches
XXS
51-52
6 3/8 – 6 1/2
20- 20 1/2
XS
53-54
6 5/8 – 6 3/4
20 7/8 – 21 1/4
S
55-56
6 7/8 – 7
21 5/8 – 22
M
57-58
7 1/8 – 7 1/4
22 1/2 – 22 7/8
L
59-60
7 3/8 – 7 1/2
23 1/4 – 23 5/8
XL
61-62
7 5/8 – 7 3/4
24 – 24 3/8
XXL
63-64
7 7/8 – 8
24 3/4 – 25 1/4
XXXL
65-66
8 1/8 – 8 1/4
25 5/8 – 26
Youth S
49-50
6 1/8 – 6 1/4 19 1/4 – 19 3/4
Youth M
51-52
6 3/8 – 6 1/2 20 – 20 1/2
Youth L
53-54
6 5/8 – 6 3/4 20 7/8 – 21 1/4
Youth S/M
49-50
6 1/8 – 6 1/4
19 1/4 – 19 3/4
Youth L/XL
51-52
6 3/8 – 6 1/2
20 – 20 1/2

Nolan Helmets Size Chart

Size Inch Around Hat Size cm
X-Small 20-7/8 6-5/8 54
Small 21-5/8 6-7/8 56
Medium 22-1/2 7-1/8 58
Large 23-1/4 7-3/8 60
X-Large 24 7-5/8 62
XX-Large 24-7/8 7-7/8 64
XXX-Large 25-5/8 8-1/8 66

Shark Helmet Size Chart

This Shark Helmet Size Conversion Chart will help you to determine what Shark helmet size will provide you with the best fit.

Shark Helmets

SIZE
METRIC(cm)
X-Small
53/54
Small
55/56
Medium
57/58
Large
59/60
X-Large
61/62

Shoei Helmet Size Chart

This Shoei Helmet Size Conversion Chart will help you to determine what Shoei helmet size will provide you with the best fit.

Shoei Helmets

INCHES
SIZE
METRIC(cm)
20 1/2
XX-Small
52
20 7/8
X-Small
54
21 1/4
Small
56
22 1/4
Medium
58
23
Large
60
23 7/8
X-Large
62
24 1/2
XX-Large
64

Suomy Helmet Size Chart

This Suomy Helmet Size Conversion Chart will help you to determine what Suomy helmet size will provide you with the best fit.

Suomy Helmets

INCHES
SIZE
METRIC(cm)
20 1/2 – 20 7/8
X-Small
53-54
21 1/4 – 21 5/8
Small
55-56
22 – 22 1/2
Medium
57-58
22 7/8 – 23 1/4
Large
59-60
23 5/8 – 24
X-Large
61-62
24 1/2 – 24 7/8
XX-Large
63-64
25 1/4 – 25 5/8
XXX-Large
65-66