A youth motorcycle helmet size chart maps a child’s head circumference to the correct helmet size, but the exact numbers change by brand — measuring just above the eyebrows is the only reliable starting point.
Kids’ helmets aren’t one-size-fits-all, even within a single brand. The fix isn’t a universal chart — it’s knowing how to measure, which numbers matter, and how to check that the helmet actually fits before the first ride.
How to Measure a Child’s Head for a Motorcycle Helmet
Use a soft cloth measuring tape. Place it about one inch above the eyebrows, circling the widest part of the head — roughly centered above the ears. Keep the tape snug against the skin but not tight enough to compress it.
Write down the circumference in centimeters (most youth helmet charts use cm, not inches). This single number is what you’ll compare to every brand’s chart.
Representative Youth Helmet Sizes by Brand
Every manufacturer publishes its own chart, and they do not match each other. Here are three widely used youth ranges from trusted brands:
| Brand | Youth Sizes (Circumference) | Notes |
|---|---|---|
| Bell Helmets | Check Bell’s live size chart — ranges vary by model line | Bell publishes model-specific charts; always use the chart for the exact helmet you’re buying |
| 100% | S = 47–48 cm, M = 49–50 cm, L = 51–52 cm | Cheek pads use Universal Fit; liners come in S, M, L for fine-tuning |
| Fox Racing | Check Fox’s official fit guide for the specific helmet | Fox offers multiple shell shapes; same size number may not fit the same across models |
The takeaway: always open the exact size chart for the model you’re buying — not a “youth chart” from a different brand or even a different helmet in the same lineup.
Using the Chart: Step by Step
Once you have the head circumference, find the row on the brand’s chart where that number falls.
When the helmet arrives, put it on and tighten any dial-adjust system at the back. Buckle the chin strap and adjust it until the strap is snug under the chin. Move the head up and down and side to side; the helmet should stay in place without rolling or sliding. Check for pressure points — a snug helmet should not cause sharp pain anywhere, including the forehead or temples. For models with removable cheek pads or liners, some brands sell thicker or thinner inserts to dial in the fit.
The Biggest Mistakes Parents Make
- Measuring too low — the tape must sit just above the eyebrows, not across the middle of the forehead. A low measurement produces a too-small helmet.
- Buying by age — age is meaningless for helmet fit. Two 8‑year‑olds can differ by several centimeters. Always measure.
- Using one brand’s chart for another brand — a 51‑cm head might be L in 100% and M in Bell. Cross‑brand assumptions cause returns.
- Ignoring cheek pads and liners — a helmet that fits the crown but pinches the cheeks or wobbles because the liner is wrong isn’t the right helmet yet.
- Treating a bike helmet chart the same as a motorcycle chart — bicycle and motorcycle helmets follow different safety standards and fit differently. Use only the motorcycle brand’s own chart.
Ready to pick a helmet after finding the right size? Check our hands‑on roundup of the best youth motorcycle helmets tested for fit and safety.
FAQs
Can I use a bike helmet size chart for a motorcycle helmet?
No. Bicycle and motorcycle helmets are tested under different safety standards and often use different head forms. Always use the motorcycle brand’s own size chart for the specific model you’re buying.
What if the child’s head measurement falls exactly between two sizes?
Most youth helmet guides recommend choosing the smaller size for a snug fit, but this varies by brand — check the brand’s own advice for that model.
Do all youth helmets come with adjustable cheek pads?
Not all models do. Brands like 100% offer Universal Fit cheek pads with separate liner sizes for fine-tuning. Other brands may mold the cheek area into the shell. Check the product specs before ordering.
References & Sources
- Bell Helmets. Bell Helmet Size Chart Official size chart for Bell models; verify against the specific helmet.
- 100%. Youth Helmets Size Guide Detailed youth sizing with cheek pad and liner compatibility notes.
- Fox Racing. Helmet Fit Guide Official fit guidance and size chart for Fox helmets.