Kids' ski helmet size chart, by the one measurement that works

The chart

This is the table almost nobody publishes: the same head measurement read across three brands at once, taken from each maker’s own published size range. Measure once, then read across.

How to measure a head, in four steps

1. Use a soft tailoring tape. If you only have a rigid one, run a piece of string around the head instead and then measure the string against a ruler.
2. Put the tape around the head about 1 cm above the eyebrows at the front and over the widest point at the back, which is usually just above the bump at the base of the skull.
3. Keep the tape level all the way round. A tape that dips at the back reads short and buys you a helmet that is too small.
4. Read the number in centimeters and write it down. Measure twice; a half-centimeter error is a size on a child.

Hair matters more than people expect. Measure with the hair the child will actually ski in, and if that is a thick ponytail, measure with the ponytail where it will sit under the helmet.

Why age charts do not work

Almost every result you will find for this question is a table of ages, and the reason it is useless is straightforward: head circumference varies enormously between children of the same age. Two seven-year-olds can sit a full helmet size apart, which means an age chart is right for some children and confidently wrong for others, with no way to tell which one you have.

A measurement takes ninety seconds and is right for your child specifically. Every brand publishes its ranges in centimeters for exactly this reason, and this page just puts three of them next to each other.

The five-second fit check, once it arrives

Measuring gets you the right size to order. This tells you whether it fits.

1. Put the helmet on without fastening the chin strap. It should sit level, with the front edge about two fingers’ width above the eyebrows.
2. Ask the child to shake their head side to side and then nod. The helmet should move the skin of the forehead rather than sliding over it. If it slides, it is too big.
3. Tighten the dial at the back until it is snug without leaving a red line on the forehead after a minute.
4. Fasten the chin strap. Two fingers should fit between the strap and the chin, and no more.
5. Put the goggles on. There should be no strip of bare forehead between the top of the goggles and the helmet brow. More on that fit here.

How much room to leave for growing

None. This is the one item on this site where sizing up does not work: a helmet that moves does not protect, so the correct size is the one that fits today.

What does buy you a second season is the adjuster. Giro publishes 6 cm of dial range inside a single size on its youth helmet, which is roughly two years of head growth on most children. That published number is worth more than any amount of buying big, and it is why we score size adjustability as part of the fit axis in our ranking method.

Once you know the size

Two things matter after fit, and both are published: the certification, which should be ASTM F2040 or CE EN 1077 and ideally both, and whether the helmet carries a rotational-impact liner such as MIPS. Our children’s helmet picks are ranked on exactly those, with cost per day on snow alongside.

Before you buy, it is worth spending two minutes on whether to buy at all. For helmets the answer is usually yes even for a child, because rental helmets are the worst-fitting item in any rental fleet, but the arithmetic is on that page rather than asserted here.

The three mistakes we see most

• Buying a size up to last two seasons. It does not work with helmets. Buy for today and buy a dial.
• Buying a used helmet. A helmet protects by crushing, and a crushed liner does not crush twice. You cannot see whether it has already done its job once, so a hand-me-down helmet is the one hand-me-down to refuse.
• Measuring over a thick hat. A modern ski helmet is lined and worn over a thin balaclava at most. Measuring over a wool hat gives you a helmet a size too big.