How should a full-face motorcycle helmet fit? A step-by-step sizing guide

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A helmet that is too big does not protect you properly: in an impact it moves and your head hits the inside. One that is too small will give you a headache within twenty minutes. Getting the size right matters as much as choosing a good model.

Step 1: measure your head

1. Use a soft tape measure.
2. Wrap it one finger above your eyebrows and above your ears.
3. Go around the widest part at the back of your head.
4. Measure two or three times and use the largest figure.

Step 2: check the brand’s chart

This table is only a rough guide. Every maker has its own sizing, and one brand’s M is not another’s:

If you are between two sizes, try both.

Step 3: check the fit

With the helmet on and fastened:

• Cheeks pressed, almost pushing your lips forward.
• No gaps at the forehead or the back of the head.
• Hold the helmet and move it: the skin on your forehead should move with it. If the helmet turns on its own, it is too big.
• With the strap fastened, try to roll it forward from the back: it should not come off.

Step 4: the 20-minute test

Keep it on for 15-20 minutes. If a pressure point appears, usually on the forehead, that helmet is not the right shape for your head, even if the size is right. Try another brand.

Head shape and shell sizes

Heads vary from round to long oval, and each brand has its own internal shape. That is why one brand fits you perfectly and another does not.

If you wear a very small or very large size, look for a helmet made in several shell sizes, so the outer shell is in proportion to your head.

A new helmet beds in

The lining compresses a little with use. So if a helmet feels completely comfortable in the shop, it will probably end up too big. Better slightly snug.

Not sure which helmet to go for? Try our helmet finder.