A bicycle helmet should be properly fitted, adjusted, and worn each time you ride. Helmets come in various sizes and can vary by manufacturer.
Size
Measure your head for approximate size. Try the helmet on to ensure it fits snugly. While it is sitting flat on top of your head, make sure the helmet doesn't rock side to side. Sizing pads come with new helmets. Use the pads to securely fit the helmet to your head. Mix or match the sizing pads for the greatest comfort. When your child's head grows, remove the padding. If the helmet has a universal fit ring instead of the pads, adjust the ring size to fit the head.
Position
The helmet should sit level on your head and low on your forehead—one or two finger-widths above your eyebrow.
Buckles
Center the left buckle under the chin. On most helmets, the straps can be pulled from the back of the helmet to lengthen or shorten the chin straps. The helmet is easier to adjust if you take it off.
Side straps
Adjust the slider on both straps to form a "V" shape under, and slightly in front of, the ears. Lock the slider if possible.
Chin strap
Buckle your chin strap. Tighten the strap until it is snug, so that no more than one or two fingers fit under the strap.
Final fitting
To check if your helmet fits right, open your mouth wide as if taking a big yawn. The helmet should pull down on the head. If not, refer back to the chin strap step above and tighten the chin strap.
If your helmet rocks back more than two fingers above the eyebrows, unbuckle and shorten the front strap by moving the slider forward. Buckle, retighten the chin strap, and test again.
If your helmet rocks forward into your eyes, unbuckle and tighten the back strap by moving the slider back toward the ear. Buckle, retighten the chin strap, and test again.
Roll the rubber band down to the buckle. All four straps must go through the rubber band and be close to the buckle to prevent the buckle from slipping.
Buy a helmet that fits the person's head now. Don't buy a helmet to grow into it. Replace any helmet that has been outgrown.
The helmet should be comfortable. If it feels small, use thinner sizing pads or buy a larger helmet. Ideally, select a helmet brand and size that fits well prior to any adjustments.
Replace any helmet that has been involved in a crash or is damaged.
Helmet laws
In Florida, a helmet must be worn by all bicyclists under 16 years old. A properly fitted bicycle helmet significantly reduces the risk of head and brain injury. Many bicycle crash injuries involve the head.
Model safe behavior
Everyone should wear a bicycle helmet each time they ride. Helmets are the single most effective way to prevent head injuries resulting from bicycle crashes. Wearing a helmet each ride can encourage the same smart behavior in others.
Helmet certification
Buy a new helmet that has been tested and meets the uniform safety standard issued by the U.S. Consumer Product Safety Commission. Use an old helmet only if it has a seal from one or more of the voluntary bicycle helmet standards, such as ASTM, Snell or ANSI. Look for the certification seal labeled on the helmet.