Helmet Size Guide for Kids: How to Measure Your Child's Head & Choose the Right Fit
Buying an ISI certified kids helmet is the first step — but a helmet that doesn't fit properly is almost as dangerous as no helmet at all. A loose helmet can fly off in an accident, while a too-tight helmet causes discomfort and means your child will resist wearing it. This guide will help you measure your child's head correctly and choose the perfect fitting kids helmet.
Why Helmet Fit is Critical for Children
Children's heads are proportionally larger relative to their body size than adults, and their neck muscles are weaker. This means:
- An ill-fitting helmet can shift during a fall, leaving the head unprotected
- A helmet that's too heavy or too large strains the neck
- A properly fitted helmet stays in place and absorbs impact correctly
Step-by-Step: How to Measure Your Child's Head
You'll need a flexible measuring tape (or a piece of string and a ruler).
- Position the tape – Place the measuring tape about 2.5 cm (1 inch) above the eyebrows, across the forehead
- Wrap around – Bring the tape around the widest part of the head, just above the ears and around the back of the head at the occipital bone (the bump at the back)
- Read the measurement – Note the circumference in centimetres
- Measure twice – Take 2-3 measurements and use the largest reading
Kids Helmet Size Chart (General Guide)
| Head Circumference | Approximate Age | Helmet Size |
|---|---|---|
| 48–50 cm | 2–3 years | XS |
| 50–52 cm | 3–5 years | S |
| 52–54 cm | 5–7 years | M |
| 54–56 cm | 7–10 years | L |
| 56–58 cm | 10–12 years | XL |
Note: Age is a rough guide only. Always go by head circumference measurement, not age.
How to Check if a Helmet Fits Correctly
Once you have the helmet on your child's head, do these checks:
- The two-finger rule – You should be able to fit two fingers between the eyebrows and the helmet's front edge. If you can fit more, it's too big.
- The shake test – Have your child shake their head side to side and up and down. The helmet should move with the head, not independently.
- The push test – Push the helmet from side to side. It should not shift more than about 1 cm.
- The chin strap – Fasten the chin strap. You should be able to fit two fingers under the strap, but no more.
- Comfort check – Ask your child if it feels comfortable. There should be no pressure points, but it should feel snug all around.
Common Mistakes Parents Make When Buying Kids Helmets
- ❌ Buying a size up "to grow into" – A loose helmet is dangerous. Buy the right size now and replace when they grow.
- ❌ Going by age instead of measurement – Children's head sizes vary enormously. Always measure.
- ❌ Ignoring the chin strap – A helmet without a properly fastened chin strap can come off in an accident.
- ❌ Keeping a helmet after a crash – Even if it looks fine, the foam inside may be compressed. Replace after any significant impact.
When to Replace Your Child's Helmet
Replace your child's helmet if:
- It has been in an accident or dropped from height
- Your child has outgrown it (the head circumference has increased)
- The foam lining is compressed or damaged
- The chin strap or buckle is broken
- It is more than 5 years old
Shop ISI Certified Kids Helmets at Xinor
Xinor's range of ISI certified kids helmets are available in sizes suitable for children aged 3–12 years. Our popular Pokémon kids helmets and Captain America kids helmets come in fun designs that make children excited to wear their safety gear — in the right size, of course!
If you're unsure about sizing, contact us and we'll help you find the perfect fit for your child.