Motorcycle Helmet Size Chart

Getting the size right is the single most important step in buying a helmet — a lid one size too big can move or come off in a crash, and one too small gives you a pressure headache you'll never wear. This chart maps your head circumference to a general helmet size, but read the warning first: sizing varies by brand and model, so this is a starting point, and you must confirm against the specific helmet's own chart before you buy.

How to measure your head

Wrap a soft cloth tape measure (or a piece of string you then measure against a ruler) around the widest part of your head — about one inch (2.5 cm) above your eyebrows and above your ears, where the skull is broadest. Keep the tape level, pull it snug but not tight, and take the measurement two or three times, using the largest reading. That number is your head circumference. Our measuring guide walks through it in full detail.

General helmet size chart

Match your measured circumference to the size below. These are typical industry ranges; individual brands shift the boundaries, so treat any value near a size break as "try both."

If your measurement falls right on a boundary, size downfirst — a helmet breaks in and loosens 15-20% as the comfort padding compresses, so a new lid should feel snug. A helmet that's comfortable in the shop will usually be too loose within a month.

Why brand charts always win

Two helmets marked "Large" from different brands can fit differently, because each maker sets its own size boundaries andits own internal head shape. That's why this chart is only a starting point: always pull up the exact model's size chart and measure to it. Just as important is shape— a helmet in your correct circumference will still hurt if its internal shape (round, intermediate oval, long oval) doesn't match your head. Learn yours on our head shapes page, because size and shape together decide the fit, and the fit decides your protection.