Does a motorcycle helmet expire after five years?

No consumer standard voids a helmet at a fixed age; the date inside is a date of manufacture, not a use-by date. Five years is a recommendation from Snell and several manufacturers, and Snell says unused, well-stored helmets do not automatically expire. The best independent aging data, from bicycle helmets, found no loss of impact performance with age. The stronger reason to replace an old, well-used helmet is fit: compacted pads leave it looser on your head.

I dropped my helmet off the motorcycle seat. Do I need a new one?

Snell, Shoei, and Arai agree that a low drop with no head inside generally does not ruin a helmet, because without the head's mass the liner is not significantly compressed. Replace it if the shell shows visible damage, and replace it after any impact that happens while you are wearing it, even if it looks fine.

Is it OK to buy a used helmet?

It is discouraged by every serious source. You cannot verify impact history because liner damage is invisible, the pads are compacted to the previous owner's head, warranties do not transfer on private sales, and missing internal labels can signal a counterfeit. New DOT-certified helmets start under $100, so the savings rarely justify the unknowns.

Can the manufacturer inspect my helmet after a crash?

Usually not in a way that clears it for further use. Shoei Europe states that post-accident clearance is not possible, and Arai says it can only assess surface damage and give an opinion, because the energy-absorbing liner is bonded in and damage is internal. Shoei's US arm has historically offered an inspection program, so practice varies by region, but the consistent guidance is to replace after any impact worn.

Which matters more, fit or rating?

Fit first. The COST 327 accident study found 13-14% of helmets came off during the crash itself, and a helmet that leaves your head cannot use any of its rated performance. Narrow your choice to helmets that fit correctly, then compare published ratings among those.

Updated 2026-07-18

Helmet fit, age, and when to replace

How to check that a helmet fits before you look at ratings, what the one-impact design of EPS liners means for replacement, and what the published evidence says about the five-year rule.

Fit comes before the rating

A rating describes how a helmet performed in a lab. Whether that performance is available to you in a crash depends first on whether the helmet stays on your head and in position. The European COST 327 accident study found that 13–14% of helmets came off during the crash itself^[1], and SHARP, the UK government's rating scheme, builds its fit guidance around that finding: even a five-star helmet cannot help if it is not on your head at the point of impact^[2].

The practical consequence is that a mid-priced helmet that matches your head shape and sits snugly is a sounder choice than a flagship that rocks or slides. Check fit first, then compare rated performance among the helmets that pass.

Fit checks in plain steps

These checks come from SHARP's fit guidance, Snell, and retailer fitting guides^[2]^[3]^[4].

Measure. Use a soft tape just above the eyebrows and ears, around the widest rear point of the skull^[2]^[3].
Match the shape. Heads fall into three fit shapes — long oval, intermediate oval, round oval — seen from above with hair flattened; intermediate oval is the most common in the US market. Forehead pressure suggests the helmet is too round for you; temple pressure suggests it is too long-oval. These are manufacturer fit descriptors, not standardized terms^[3].
Cheek pads. In a full-face helmet the pads should press firmly against your cheeks. Grab the chin bar and rotate the helmet: your cheeks and skin should move with it. If the helmet slides on your head, it is too big — go down a size. Many models accept different pad thicknesses to fine-tune fit^[2]^[3].
Roll-off check. Fasten the chin strap, tilt your head forward, and have someone push up on the rear base of the helmet, trying to roll it forward off your head. If it rolls off in the shop, it can come off in a crash. The strap should be tight enough that you can still open and close your mouth^[2]^[4].
Wear it. Keep it on 15–30 minutes before buying; Snell advises at least 5–10 minutes and notes most people buy one size too big. A pressure point that shows up at 15 minutes becomes painful on a long ride^[3]^[4].

One impact by design

The energy-absorbing EPS liner works by crushing permanently — it does not spring back — so a helmet is built to protect in one impact, and liner damage is usually invisible from outside^[4]^[5]^[6]. Replace-after-impact is the one rule in the strongest evidence tier: it is manufacturer guidance, certifier guidance, and legally mandated US label text. Every DOT-certified helmet must carry the instruction that after a severe blow the helmet should be returned to the manufacturer for inspection, or destroyed and replaced^[7]. Replace a helmet after any impact that happened while it was on your head, even if it looks fine.

Two related points sit one tier down, as manufacturer and certifier consensus rather than independent published testing. First, a helmet dropped from bench or seat height with no head inside is generally not ruined: without the head's mass the liner is not significantly compressed by a low fall. Replace it if the shell shows visible damage; repeated hard drops can degrade a helmet over time^[4]^[5]^[6]. Second, do not count on an inspection to clear a crashed helmet: Shoei Europe states that post-accident clearance is not possible, and Arai says it can only assess surface damage and offer an opinion^[5]^[6]. Practice varies by region — Shoei's US arm has reportedly offered an inspection program.

The five-year rule, sorted by evidence

Age-based replacement guidance is where the evidence tiers separate, so we label each claim by its type.

Certifier recommendation. Snell recommends replacement after about five years of normal use. Its stated mechanism is mostly fit, not chemistry: putting a helmet on and taking it off wears the comfort pads and liner, and worn-out pads leave a helmet fitting one to two sizes larger — looser, more likely to shift or come off in a crash. Snell is explicit that unused, well-stored helmets do not automatically expire at five years^[4].
Manufacturer claims. Arai advises replacement 7 years after manufacture or 5 years after purchase; Shoei recommends replacement after about 5 years of normal use. Both attribute this to EPS material degradation, but neither publishes supporting test data, so we treat these as attributed claims, not established fact^[5]^[6].
Independent published testing. The largest aging study, from MEA Forensic (2017), drop-tested 770 field-used bicycle helmets aged 0 to 26 years at 3.0 and 6.2 m/s and found no loss of impact attenuation with age — at worst a statistically significant but tiny rise in peak headform acceleration of up to 0.76 g per year^[8]. The caveat matters: these were bicycle helmets, and no equivalent published aging study exists for motorcycle helmets. The liner is the same material class (EPS), but the study did not evaluate strap or comfort-pad wear — the fit mechanism Snell cites^[8]^[9].
Commercial pressure. The Bicycle Helmet Safety Institute (a bicycle-helmet group; read its guidance in that context) documents commercial pressure toward short intervals: it calls Bell's 3-year recommendation too short, and notes that Italian maker MET's own testing supported 8 years of service before the company shortened its public recommendation to 3–5 years^[9].

Where that leaves you: replace after any worn impact. Treat the five-year clock as a reasonable maintenance recommendation — its fit-degradation rationale is real — rather than a tested expiry. The date of manufacture printed inside the helmet is a birth date, not a use-by date; no consumer standard voids a helmet at a fixed age^[4]^[7]. If the pads have compacted and the helmet now moves on your head, that is the signal that matters. Racing and track-day organizations may set stricter helmet-age limits — see track day gear requirements.

Buying used: what you cannot check

Serious sources consistently discourage used helmets, for reasons that follow from the one-impact design^[4]^[10].

Impact history is unverifiable. EPS damage is internal and invisible, and a seller's memory is not an inspection^[5]^[10].
The pads have compacted to the previous owner's head, so the fit you feel is degraded from new^[4]^[10].
Warranties do not transfer on private sales — Arai states this explicitly^[6].
Missing internal certification or manufacturer labels are a flag for counterfeits. Our label decoder shows what should be present^[10].

New DOT-certified helmets start under $100, which weakens the economic case for taking on unknowns^[10]. For what the certification marks themselves mean, see helmet standards explained; for how we grade evidence, see our methodology.

Common questions

Does a motorcycle helmet expire after five years?: No consumer standard voids a helmet at a fixed age; the date inside is a date of manufacture, not a use-by date. Five years is a recommendation from Snell and several manufacturers, and Snell says unused, well-stored helmets do not automatically expire. The best independent aging data, from bicycle helmets, found no loss of impact performance with age. The stronger reason to replace an old, well-used helmet is fit: compacted pads leave it looser on your head.
I dropped my helmet off the motorcycle seat. Do I need a new one?: Snell, Shoei, and Arai agree that a low drop with no head inside generally does not ruin a helmet, because without the head's mass the liner is not significantly compressed. Replace it if the shell shows visible damage, and replace it after any impact that happens while you are wearing it, even if it looks fine.
Is it OK to buy a used helmet?: It is discouraged by every serious source. You cannot verify impact history because liner damage is invisible, the pads are compacted to the previous owner's head, warranties do not transfer on private sales, and missing internal labels can signal a counterfeit. New DOT-certified helmets start under $100, so the savings rarely justify the unknowns.
Can the manufacturer inspect my helmet after a crash?: Usually not in a way that clears it for further use. Shoei Europe states that post-accident clearance is not possible, and Arai says it can only assess surface damage and give an opinion, because the energy-absorbing liner is bonded in and damage is internal. Shoei's US arm has historically offered an inspection program, so practice varies by region, but the consistent guidance is to replace after any impact worn.
Which matters more, fit or rating?: Fit first. The COST 327 accident study found 13-14% of helmets came off during the crash itself, and a helmet that leaves your head cannot use any of its rated performance. Narrow your choice to helmets that fit correctly, then compare published ratings among those.