How to Choose the Right Helmet Size for Your Child: Banwood Sizing Guide

Quick answer

Measure your child's head circumference about 2 cm above the eyebrows with a soft tape, then compare it to the helmet's stated range. The Banwood Helmet in Pink is sized 50–54 cm and uses dial-fit adjustment, so it fits most children within that band. If your child measures under 50 cm, wait or choose a smaller certified helmet; if over 54 cm, size up rather than squeezing.

A helmet only protects when it fits, and a loose or tilted helmet can slide on impact. Most parents buy by age, but head circumference is the number that matters. This guide walks you through measuring at home, reading a size range correctly, and checking the fit in under a minute.

We'll use the Banwood helmet as a concrete example because it has a clear 50–54 cm range and a dial-fit system. You'll also learn the two tests that tell you whether the helmet is actually safe to ride in.

How to measure your child's head correctly

Use a soft measuring tape or a piece of string you later lay against a ruler. Wrap it around the widest part of the head, roughly 2 cm above the eyebrows and around the back where the skull slopes outward. Keep the tape snug but not tight, and measure twice to confirm. Do this when your child is calm and looking straight ahead.

Write down the measurement in centimetres. If it lands exactly on the edge of a size range, like 50 cm or 54 cm, treat the fit as borderline and test with the helmet on before committing. Hair thickness and how your child wears their hair can shift the number by a centimetre, so remeasure on a normal hair day.

• Measure at the widest point, not across the forehead.
• Take two readings and use the larger one.
• Recheck every 3–6 months; young heads grow quickly.

Reading a helmet size range: what 50–54 cm really means

A range like 50–54 cm means the helmet's internal adjustment can cover heads within that span, not that every head in it gets the same fit. The Banwood Helmet in Pink uses a dial-fit adjustment system and an adjustable chinstrap, so you fine-tune the circumference after choosing the size. That adjustability is why a range works for growing kids.

If your child measures below the minimum, the helmet may sit too low or need over-tightening, which can cause pressure points. If above the maximum, the shell won't cover the head properly. In both cases, choose a different size rather than forcing the fit.

• Below the minimum: choose a smaller size, not a tighter dial.
• Above the maximum: size up to the next range.
• At the edge: test in person if possible.

The two fit tests every parent should do

First, the eyebrow test: with the helmet level, the front edge should sit about one to two finger-widths above the eyebrows. If it covers the eyebrows, it's too low and will block vision; if it sits high on the forehead, it won't protect the front of the head. Second, the rock test: with the chinstrap fastened, gently push the helmet from side to side and front to back. The skin should move slightly with the helmet, and the helmet should not slide more than about a centimetre.

The chinstrap should form a V just under each ear and allow one finger between the strap and the chin. A strap that's too loose lets the helmet shift in a fall; too tight is uncomfortable and your child will resist wearing it. Check both tests before every ride, because straps loosen over time.

• Eyebrow test: one to two finger-widths above the brows.
• Rock test: helmet moves less than about a centimetre.
• Chinstrap: V under the ears, one finger under the chin.

When to size up and when to replace

Size up when your child's measurement moves past the top of the range or when the dial is fully tightened and the helmet still rocks. Replace the helmet after any crash that involves a hard impact, even if there's no visible damage, because the foam liner can compress internally. Also replace it if the straps fray, the dial stops holding, or the shell shows cracks.

As a practical habit, recheck the fit at the start of each season and after a growth spurt. A helmet that fit in spring may sit too high by autumn. Keeping the measurement written down makes it easy to spot the change.

• Replace after a hard impact, regardless of appearance.
• Replace if the dial no longer holds adjustment.
• Recheck fit seasonally and after growth spurts.

Decision rules for choosing a helmet size

• Head measures 48–49 cm: Below the Banwood 50–54 cm range. Choose a smaller certified helmet or wait until the measurement reaches 50 cm. Don't buy a 50–54 cm helmet hoping the dial will close the gap.
• Head measures 50–54 cm: Within the Banwood Helmet range. Fit the helmet level, tighten the dial until it's snug, then run the eyebrow and rock tests. This is the intended fit band; adjust the chinstrap to a V under the ears.
• Head measures 55 cm or more: Above the Banwood 50–54 cm range. Size up to the next available range rather than over-tightening. A helmet that sits too high leaves the front of the head exposed.
• Borderline measurement (50 or 54 cm): Test with the helmet on before committing. If the dial is at either extreme, consider the adjacent size. Hair thickness and growth can push a borderline fit out of range within months.

Product facts that affect fit

• BANWOOD HELMET - PINK (50-54 cm): Made with an in-mould ABS shell, EPS foam liner and a vegan leather strap, with a dial-fit adjustment system and adjustable chinstrap. The dial-fit system is what lets one 50–54 cm helmet cover a growing child for more than a single season, and the adjustable chinstrap helps you pass the rock test.
• BANWOOD BALANCE BIKE FIRST GO VINTAGE - BEIGE: Designed for children ages 3 to 5 who are learning to balance before moving on to a pedal bike, with no training wheels. If your child is in this age and stage, the 50–54 cm helmet range is the one to measure against before you buy the bike.

Who the Banwood 50–54 cm helmet fits

Best for

• Children whose head circumference measures between 50 and 54 cm
• Parents who want a dial-fit helmet that adjusts as their child grows
• Kids aged roughly 3–5 who are starting on a balance bike like the Banwood First Go

Not for

• Children measuring under 50 cm, who need a smaller certified helmet
• Children measuring over 54 cm, who need to size up
• Anyone who wants a one-size-fits-all helmet without measuring first

Measure first, then match the number to the helmet's range. The Banwood 50–54 cm helmet with dial-fit adjustment covers most children in that band, but no dial can fix a head that sits outside the range. Take three minutes with a soft tape, run the eyebrow and rock tests, and recheck the fit each season.