Helmet Size Converter
Enter your head circumference — get your helmet size for bike, motorcycle, ski/snow, and climbing. Includes safety standards.
Safety standards by helmet type
Bike
US: CPSC required. Europe: EN 1078. MIPS add-on (Multi-directional Impact Protection System) is worth the upcharge — reduces rotational forces in oblique impacts.
Motorcycle
US: DOT FMVSS 218 minimum. Look for ECE 22.05/22.06 (European) or SNELL M2020 (highest standard, used by racing). Avoid novelty/unmarked helmets — they don't pass impact testing.
Ski / snowboard
US: ASTM F2040. Europe: EN 1077. Some helmets are dual-certified for ski AND climbing.
Climbing
UIAA 106 or EN 12492. Designed for top-down impacts (falling rocks). NOT rated for side impacts like bike helmets.
Don't substitute
Bike helmets aren't rated for motorcycling. Ski helmets don't protect against rockfall. Use the right helmet for the activity — they're engineered differently.
FAQ
How long does a helmet last?
Bike/ski: 3–5 years OR after any impact. Replace immediately if dropped on a hard surface.
Motorcycle: 5 years or after impact. EPS foam degrades regardless of use.
Can I wear a bike helmet for a scooter?
Electric scooters < 20mph: yes, bike helmet is acceptable. > 20mph or moped: get a DOT motorcycle helmet.
Is MIPS worth the extra cost?
Yes — independent crash testing shows MIPS reduces brain injury risk in oblique impacts. Adds $20–60. Worth it for any helmet you wear regularly.
What about kids helmets?
Always buy youth-specific (CPSC has a separate kids standard). Kids' heads grow ~1cm/year — replace every 2 years even without impact. Should have rear adjustment dial for fine fit.