Bicycle Helmet Laws in California
Last reviewed by BikeSize EditorialThis guide is for general information only and is not legal advice. Laws change - verify current rules with your state DOT or a licensed attorney before relying on this for any legal matter. Read full disclaimer.
The rule
California requires a bicycle helmet for every rider under 18 — in practice, every rider except adults aged 18 and over. The same rule extends to children carried as passengers in a child seat or trailer. Fine of up to $25 for a first offense; courts often waive or reduce the fine on proof of helmet purchase and completion of a bicycle-safety course. See Cal. Veh. Code § 21212. Read the national helmet laws guide for comparison. Confirm equipment fit with the helmet size calculator before relying on an age rule alone.
Statute
What this means in practice
If you're 18 or older, California doesn't require you to wear a helmet by state law. Riders under 18 (and any child carried as a passenger) must wear a helmet that meets the CPSC standard.
Cities can be stricter than the state floor, and bike-share systems often require helmets regardless of age. If you're renting or commuting in a major city, confirm the local rule before you ride.
Get the fit right
Find your CPSC-certified helmet size
A helmet that meets the law but does not fit will not protect you. Measure your head circumference, then shop a size band you can trust.
Open the helmet size calculator