Helmet Size Conversion Charts

This helmet size chart has been compiled from helmet manufacturers' literature, sizing charts and years of experience assisting customers with helmet purchases. Not all helmets are created equal. Just because you wear a medium Shoei doesn't mean a medium Arai or Bell will fit.

Measure Your Head

Even if you say you know your size, a good salesperson will still measure your head. Due to different shapes, heads that are apparently the same size when measured with a tape may not necessarily fit the same size helmet.

Measure the circumference (all the way around) of the head at a point approximately one half to one inch above the eyebrows, and at a point on the back of the head that results in the largest possible measurement. Take several measurements, to make sure you have the largest one. Use that one to determine your size. The standard procedure is measure your head to get your size, put the helmet on & shake your head a little, see how it feels. Have you ever gotten your head stuck in a helmet that was too small? It is not pretty. It is funny for your friends, but you won't like it. It should be snug, but not cutting off the circulation to your scalp or making your eyes bulge. On the other end of the spectrum when people start way too large, the helmet goes on easily then they shake their head and the helmet goes bouncing down the aisle. When you shake your head the helmet should not move more than 1/4". If the lid shifts on your head just shaking it a little, imagine what it will do on the bike at 65mph. The wind can get under it and it starts to lift or roll back farther on your head. Regardless of DOT or Snell rating, an ill fitting helmet will not offer the maximum protection in a crash. You can live without a leg or an arm. How many dudes do you know who have no head?

Helmet Size Conversion Chart

Brand	HelmetSize	Head -Inches	Head - cm	Hat Size
Answer	X-Small	20" - 20 1/2"	53cm	6 5/8" - 6 3/4"
	Small	21 1/2" - 22"	57cm	6 7/8" - 7"
	Medium	22 1/2" - 22 3/4"	58cm	7 1/8" - 7 1/4"
	Large	23 1/4" - 23 1/2"	60cm	7 3/8" - 7 1/2"
	X-Large	24" - 24 1/2"	62cm	7 5/8" - 7 3/4"
Arai	XXX-Small	19 1/4" - 19 5/8"	49-50cm	n/a
	XX-Small	20" - 20 3/8"	51-52cm	n/a
	X-Small	20 1/4" - 20 7/8"	53-54cm	XS  6 1/2" - 6 5/8"
	Small	21" - 21 5/8"	55-56cm	S  6 3/4" - 6 7/8"
	Medium	21 3/4" - 22 3/8"	57-58cm	M  7" - 7 1/8"
	Large	22 1/2" - 23 1/8"	59-60cm	L  7 1/4" - 7 3/8"
	X-Large	23 1/4" - 24"	61-62cm	XL  7 1/2" - 7 5/8"
	XX-Large	24 1/8" - 24 7/8"	63-64cm	XXL  7 3/4" - 7 7/8"
	XXX-Large	25" - 25 5/8"	65-66cm	XXXL  8" - 8 1/8"
Shoei	XX-Small	20 1/8" - 20 1/4"	51-52cm	n/a
	X-Small	20 7/8" - 21 1/4"	53-54cm	6 5/8" - 6 3/4"
	Small	21 5/8" - 22"	55-56cm	6 7/8" - 7"
	Medium	22 1/2" - 22 7/8"	57-58cm	7 1/8" - 7 1/4"
	Large	23 1/4" - 23 5/8"	59-60cm	7 3/8" - 7 1/2"
	X-Large	24" - 24 3/8"	61-62cm	7 5/8" - 7 3/4"
	XX-Large	24 3/4" - 25 1/8"	63-64cm	7 7/8" - 8"
	XXX-Large	25 5/8" - 26"	65-66cm	8 1/8" - 8 1/4"
Fox Racing	Youth
	KS	18 6/8" - 19 5/8"	50cm
	KM	19 1/4" - 20"	51cm
	KL	20 1/8" - 21"	55cm	XS
	Adult
	X-Small	20 1/2" - 21 1/16"	55cm	XS
	Small	21 1/4" - 22 1/8"	57cm	S
	Medium	22 3/8" - 23 1/8"	59m	M
	Large	23 1/4" - 23 3/4"	61cm	L
	X-Large	23 7/8" - 24 3/4"	63cm	XL
	XX-Large	24 7/8" - 25 3/4"	65cm	XXL
HJC	Youth S/M	19 3/4" - 20 1/8"	50-52cm	n/a
	Youth L/XL	20 1/2" - 21 1/4"	53-54cm	XS  6 5/8" - 6 3/4"
	XXX-Small	19 1/4" - 19 3/4"	49-50cm	n/a
	XX-Small	20" - 20 1/2"	51-52cm	XS  6 3/8" - 6 1/2"
	X-Small	20 7/8" - 21 1/4"	53-54cm	XS/S  6 5/8" - 6 3/4"
	Small	21 3/8" - 22"	55-56cm	S/M  6 7/8" - 7"
	Medium	22 1/6" - 22 7/8"	57-58cm	M/L  7 1/8"  7 1/4"
	Large	23 1/4" - 23 5/8"	59-60cm	L/XL  7 3/8" - 7 1/2"
	X-Large	24" - 24 1/2"	61-62cm	XL/XXL 75/8" - 7 3/4"
	XX-Large	24 3/4" - 25 1/4"	63-64cm	XXL/XXXL 7 7/8" - 8"
	XXX-Large	25 1/8" - 26"	65-66cm	XXXL  8 1/8" - 8 1/4"
Thor	XX-Small	20 1/2"	52-53cm	XS  6 1/2"
	X-Small	20 7/8" - 21 1/4"	53-54cm	XS/S  6 5/8" - 6 3/4"
	Small	21 5/8" - 22"	55-56cm	S/M  6 7/8" - 7"
	Medium	22 3/8"	57-58cm	M/L  7 1/8"  7 1/4"
	Large	22 3/4" - 23 1/8"	59-60cm	L/XL  7 3/8" - 7 1/2"
	X-Large	23 1/2" - 24	61-62cm	XL/XXL 75/8" - 7 3/4"
	XX-Large	24 3/4" - 25 1/8"	63-64cm	XXXL  7 7/8" - 8 1/8"
Bell	Youth Small	19 1/2" - 20"	50-51cm	5 7/8" - 6 1/8"
	Youth Medium	20" - 20 1/2"	51-52cm	XS  6 1/8" - 6 3/8"
	Youth Large	20 1/2" - 21"	52-53cm	XS  6 3/8" - 6 5/8"
	X-Small	20 7/8" - 21 1/4"	53-54cm	XS/S  6 5/8" - 6 3/4"
	Small	21 5/8" - 22"	55-56cm	S/M  6 7/8" - 7"
	Medium	22 3/8" - 22 3/4"	57-58cm	M/L  7 1/8" - 7 1/4"
	Large	23 1/4" - 23 5/8"	59-60cm	L/XL  7 3/8" - 7 1/2"
	X-Large	24" - 24 3/8"	61-62cm	XXL 7 5/8" - 7 3/4"
	XX-Large	24 3/4" - 25 1/4"	63-64cm	XXL/XXXL7 7/8" - 8"