A helmet only does its job if it actually fits. The right size keeps the helmet stable, comfortable, and positioned where it needs to be for protection. The good news is you only need one measurement to figure out your size: the circumference of your head.
Measure your head the right way
Grab a flexible measuring tape. If you don’t have one, use a string and measure it against a ruler afterward.
- Wrap the tape around your head about 1 cm above your eyebrows.
- Keep it level around the widest part of the back of your head.
- Pull it snug, not tight.
- Write down the number in centimeters.
Most adult heads will fall somewhere between 52 cm and 64 cm.
Compare your measurement to size ranges
Brands vary a little, but most helmets follow similar size brackets. Here’s a rough guide:
- Small: 52–55 cm
- Medium: 55–59 cm
- Large: 59–62 cm
- Extra Large: 62–64 cm
If your measurement sits at the high end of a size range, you can go up one size, especially if you prefer a relaxed fit.
Check adjustability features
Most helmets have a dial or fit system that lets you fine tune the size. This is helpful if you sit between sizes or wear your hair differently on the mountain.
A good rule: if the helmet sits on your head properly with the adjustment system fully loosened, you’re in the right size. The dial should bring it to a secure fit, not squeeze you into the helmet.
Try the fit test
Once you’ve picked a size, do a quick check.
- Put the helmet on and tighten the dial until it’s secure.
- Nod your head up and down.
- Shake it side to side.
The helmet should stay put without wobbling. You shouldn’t feel any sharp pressure points. It should rest low enough to protect your forehead but not so low that it touches your goggles.
Think about goggles
Your goggles and helmet should sit together cleanly. You want a smooth connection with no large gap at the top. If the gap is big, you may need a different helmet shape, not a different size.
When to size up or down
You can size up if:
- You want to wear a thin beanie underneath
- You’re between sizes and prefer more comfort
- You have a rounder head shape that needs more space
You can size down if:
- Your measurement is at the very bottom of a size range
- You prefer a snug, performance-oriented feel
- You plan to rely only on the helmet’s dial system for micro-adjustment
Bottom line
Helmet sizing is straightforward once you have your measurement. Use your head circumference to pick the right size bracket, then rely on the dial system to fine tune it. A helmet that fits properly will feel secure without squeezing and will stay in place when you move.
Need help finding the right measurement? You can book a fitting session with our team of experts!