How to Measure for ATV Helmet Size? | Circumference First

Measure your head circumference with a cloth tape just above the eyebrows, then match it to that helmet brand’s size chart.

Getting the right ATV helmet size comes down to one number: the circumference of your head. The tape goes around the widest part, roughly an inch above your eyebrows and around the back, and the result gets compared to the specific manufacturer’s chart. Sizing varies by brand and model, so the measurement is only the starting point — the helmet has to pass a fit test on your head too.

Measure Your Head the Right Way

You need a soft, flexible cloth measuring tape. If you don’t have one, a piece of string, rope, or even a shoelace works — wrap it around your head, mark the meeting point, then lay it flat against a ruler or metal tape measure.

Position the tape about 1 inch above your eyebrows, running it above your ears and around the largest circumference of your skull. Keep it snug but not tight — you want contact, not compression. Take two or three readings and go with the largest one if they differ.

If you plan to wear a balaclava or head sock while riding, put it on before you measure. It adds thickness that changes the fit, and measuring without it can leave you with a helmet that’s snugger than intended.

Then take that number to the manufacturer’s size chart for the exact helmet you’re buying. Polaris’s ATV helmet buying guide walks through the same method, and brands like Bell Racing USA and Fox Racing publish their own fit guides with model-specific charts.

What to Avoid When Measuring

Several common errors throw the measurement off. A metal construction tape doesn’t bend around your head the way cloth does, and it can distort the reading — skip it entirely. Measuring too high or too low misses the widest part of the skull, which is the number that actually determines fit.

Tension matters too. Pull the tape too tight and you’ll order a size too small; leave it loose and you’ll land one size too big. And don’t guess based on age — youth and adult sizes vary widely between brands, and only a measured circumference plus the chart gets you close.

Fit Check Once the Helmet Is On

The measurement narrows it down, but the helmet itself decides. A correct circumference number doesn’t guarantee the internal shape matches your head, so you have to test it on.

The helmet should sit snugly around your head and cheeks without any pressure points or hotspots. Grab the chin bar or guard and try to wiggle the helmet — minimal movement is what you want. If it slides around easily, it’s too large. If the measurement falls between sizes, the right call depends on the brand: some manufacturers’ charts suggest trying the smaller size for a closer fit, while others lean toward the larger. Check the specific chart and, when possible, try both on your head before deciding.

Once you’ve confirmed the size fits securely without significant wobble, you’re ready to ride. For a look at tested options across price points, our best ATV helmets roundup breaks down the top picks.

Why the Manufacturer’s Chart Matters

There’s no universal helmet size. A medium from one brand can fit like a large from another, and sometimes charts differ between models within the same brand. That’s why the circumference measurement always gets matched to the specific helmet’s chart — Bell Racing’s size guide and Fox Racing’s helmet fit guide both publish their own numbers.

Remember that fit is about more than circumference. Internal shape, cheek pad pressure, and how the helmet sits on your head all affect protection. A helmet that fits correctly stays in place during a crash; one that’s loose can shift and compromise coverage. The measurement gets you to the right size, but the on-head test confirms it.