Choosing a cycling helmet: the label, and the rule that decides.

What a helmet can and cannot do

Nothing on this page says a helmet is certified, safe or legal anywhere. The standard on the label, the law where it is sold or worn, and a race organiser's rules decide that. The US mandatory standard itself requires every helmet label to warn that no helmet protects against all impacts, and the Virginia Tech Helmet Lab says even the best helmet cannot prevent all head injuries.

The research is consistent on direction and disputed on size. The Cochrane review by Thompson, Rivara and Thompson (1999) found helmets reduced the risk of head, brain and severe brain injury by 63 to 88 percent among cyclists who crashed. A 2023 review of meta-analyses by Büth, Barbour and Abdel-Aty concluded helmets help regardless of age, crash severity or crash type. Rune Elvik (2011, corrected 2013) argued that one earlier meta-analysis overstated the benefit through publication and time-trend bias. The helmet evidence page sets out each review. A suspected head injury needs medical care.

The standards on the label

EN 17950:2024 is a test method for measuring rotational movement in an impact, not a helmet standard. Escape Collective reported in February 2025 that a coming European standard built on it would make rotational testing mandatory, with thresholds and an in-force date still to be agreed.

Where a standard is required for sale

• United States: CPSC Part 1203, as above. The CPSC says it covers headgear marketed for cyclists, including multi-purpose helmets a reasonable buyer could take to be for cycling.
• Australia: the Consumer Goods (Bicycle Helmets) Safety Standard 2024, registered in March 2024, requires full compliance with one of six standards: AS/NZS 2063:2008, AS/NZS 2063:2020, EN 1078:2012+A1:2012, CPSC Part 1203, ASTM F1447-18 or Snell B-95. It excludes helmets for competitive downhill and BMX racing. A search summary dates the end of its 18-month transition to 21 September 2025; we could not open the regulator's page to confirm it.
• British Columbia: B.C. Reg. 234/96 (in force 3 September 1996) lists CAN/CSA D113.2-M89, Snell B-95, B-90, B-90S, N-94, ASTM F1447-94 and ANSI Z90.4-1984.
• Europe and the UK: national catalogues link EN 1078 to the EU Personal Protective Equipment Regulation (EU) 2016/425; we did not check the Official Journal citation.

Who must wear one

• Great Britain and Northern Ireland: Highway Code Rule 59 advises a helmet that meets current standards, fits and is fastened. It is "should" guidance, not law.
• United States: GHSA records no state requiring helmets for all riders; 21 states, the District of Columbia and the Northern Mariana Islands have laws for riders under a certain age (reviewed March 2024).
• Australia: the CDC's MMWR records Victoria's law, from 1 July 1990, as the first statewide law for all cyclists. We did not collect the wearing rules of the other Australian states and territories.
• E-bikes: California's AB 1096 (2015) requires Class 3 riders and passengers to wear a helmet meeting ASTM or CPSC standards. In Great Britain, the government's information sheet (December 2024) says an e-bike that fails the assisted pedal cycle rules is treated as a motor vehicle needing a motorcycle helmet; Northern Ireland's nidirect says a compliant e-bike needs no motorcycle helmet but highly recommends a suitable one.

Racing rules

As reproduced in the Japan Cycling Federation's copy of the UCI clarification guide (edition date unconfirmed), UCI Article 1.3.031 makes a rigid helmet compulsory in competition and official training in all disciplines except indoor cycling and BMX freestyle flatland. Each rider must wear a helmet approved to an official safety standard, unaltered and not having suffered an accident or shock. Road and track helmets may be at most 450 mm long, 300 mm wide and 210 mm high, with helmets already on the market on 1 January 2023 exempt. A "traditional" helmet must have at least three air inlets, leave the ears uncovered and have no visor; "time trial" helmets are allowed only in listed events against the clock. The UCI applied these mass-start rules from 1 January 2026 in road and cyclo-cross, and from 1 January 2027 on the track. An undated UCI statement said a helmet certification protocol would come "no earlier than 1 January 2027"; we found nothing later confirming it.

USA Cycling Policy I requires licensees to wear a fastened helmet whenever they take part in, or prepare for, an event under its permit, including club rides. It accepts the CPSC standard (or the US DOT standard), says helmets with European CEN certification may be worn only in races on the UCI calendar, and exempts riders on rollers or other stationary devices. The racing rules page has more.

Independent ratings and rotational systems

The Virginia Tech Helmet Lab, with the Insurance Institute for Highway Safety, scores bicycle helmets with its STAR method: 24 impacts per helmet at 6 locations and two energies, with concussion risk worked out from linear acceleration and rotational velocity. Its page cites a July 2025 ratings update and recommends 4 or 5 star helmets. In the first ratings (IIHS, 26 June 2018), 4 of 30 adult helmets earned five stars; in the 2019 method paper by Bland and colleagues, road helmets scored better than urban ones. A rating is a lab estimate, not certification.

MIPS and other rotational-impact systems such as WaveCel are makers' technologies, and what they promise is the maker's claim; none is a regulatory standard. IIHS reported in 2018 that all four five-star helmets used MIPS, and the 2019 paper found that helmets with MIPS scored better than those without. The independent helmet tests page explains the method.

Replacing a helmet

The CPSC requires the label to say a helmet should be replaced after an impact, and the UCI rule excludes helmets that have suffered an accident or shock. We found no standards body or governing body giving a number of years after which a cycling helmet should be replaced, so we give none. Helmet fit is not described here; we suggest having it shown in person.

Our picks by category