Bike helmet size chart and how to measure for a bike helmet

May 23, 2024 10 min

Bike helmet size chart and how to measure for a bike helmet

What is the bike helmet size chart? How to measure for a bike helmet? Safety will always be the most important factor when it comes to cycling. There are many ways to keep yourself safe, such as wearing high-visibility clothing, staying off busy roads, using proper tube signals, and even having a mirror on your bike.

The best way to stay safe is to wear a bike helmet. Not only does it protect your head in the event of an accident, but it also shows other cyclists and road users that you are taking precautions.

Why are bike helmets so important?

Bike helmet size chart — Head injuries are one of the biggest causes of cycling injuries

Bike helmets are so important when it comes to cycling, and many people forget the advantages of wearing one while riding. Here’s what you need to know!

Protect you in the event of a crash

The first point is that helmets can protect you in the event of an accident. Head injuries are one of the biggest causes of cycling injuries, and many of them can be avoided simply by wearing a helmet. Protecting your head and brain is vital when riding anywhere.

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It’s in the rules and the law

If you plan on going to a cycling event, most will not let you ride without a helmet, which we completely understand. Also, in many countries now, wearing a bike helmet is the law and must be done. If not, you can get fined heavily.

It shows competence

The next important factor to mention is that wearing a bike helmet shows competence with other road users. If you wear a helmet, they know you are making an effort to stay safe, and quite often, that is respected with better driving around you.

It can help performance

Wearing a bike helmet makes a difference if you want to improve your aerodynamics and speed. If you ask a time trialist or professional cyclist, they will tell you the huge difference it can make on a windy day or a long course.

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Bike helmet size chart: First, understanding bike helmet sizing

Bike helmets are generally sized differently by each company, deepening the styles and designs of each helmet. Surprisingly, there are a lot of different styles of bike helmets on the market.

Bike helmet type	Use
Road bike helmet	Road cycling, made for aerodynamics and ventilation.
Mountain bike helmet	Mountain biking events and trail riding. Extra ventilation is often used.
Time trial helmet	For extra aerodynamics and to streamline the rider in a low position.
Full / Half face helmets	Used to very technical off road events where crashing is common.
Commuter helmets	For general commuting in a city or town. Made to be comfortable.
BMX / Skate	Used for cycling where stunts and tricks are involved, very strong.
Dual sport	Used for a mix of both road cycling and mountain biking.

Although there are many types of bike helmets, they generally follow similar sizing when it comes to having the correct fit for the user on the bike helmet size chart.

"Small, medium, and large road cycling helmets are similar to mountain bike helmets and commuter helmets." - Alice Huot @buycycle

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Want to learn more about sizing and finding your perfect fit?
- Bike size chart: What size bike do I need?
- Everything about the tire size of your bike
- Wheel bike size chart
- Bike helmet size chart
- How to calculate your ideal saddle height?

All about frame height...
- All about frame height on a mountain bike
- All about frame height for a road bike

Bike helmet size chart

Now for the bike helmet charts. These will help you determine what size helmet you need and give you the best possible chance of getting a great-fitting helmet for the first time.

Adults bike helmet size chart

Size	Head circumference
X Small	47 - 53 cm
Small	50 - 55 cm
Medium	54 - 59 cm
Large	58 - 63 cm
X Large	62 cm and above

Adult helmets are measured around the circumference of the head. We will explain how to do this later in this article. Most brands generally size small to large, but some go extra small and extra large.

"It’s good to remember that you typically also have a large amount of adjustment to play with regarding each helmet in case you are between sizing." - Anja Benson @buycycle

For example, if you are between a small and medium they will often both adjust to where you need to be.

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Children's bike helmet size chart

Size	Head circumference
Toddler	43 - 48 cm
Child	46 - 50 cm
Youth	48 - 54 cm

Children's sizing works differently from adult sizing. They size according to their age and stage of growth. It’s easy to fall into the trap of not measuring their heads when you should to ensure where they are.

How to measure for a bike helmet

Measuring your head and not just guessing is essential to get the perfect helmet fit. You could be 5ft 4” tall and require a large helmet or 6ft 5” and need a small helmet. Head size is quite unique to each person and is difficult to compare to height.

Measuring your bike helmet is easier than you might think. All you need is measuring tape or string and a ruler. Using another person to help you will make this much more manageable.

Measure the most significant part of the head above the ears and eyebrows with the tape or string. Go all the way around, and we recommend measuring multiple times. Write it down when you have your measurement so you don’t forget it. Now you know how to measure for a bike helmet.

The same process applies to measuring a child's bike helmet, measuring a dirt bike helmet, and much more.

Testing

If you don’t want to measure, another option is to test some helmets. A good way to do this is to go to your local bike shop and try different styles in different sizes. You will be able to see what works and what different styles you like.

It’s also good to speak to bike shop employees about the benefits of certain helmets and even to feel the weight of different helmets, as some can weigh a lot, and others are incredibly lightweight.

Adjustability

It’s also good to remember that helmets are very adjustable. This doesn’t mean you can use a medium if you are small. It just means they are adjustable within the sizing range you are choosing.

What to look for in a bike helmet

Regarding finding the right bike helmet, there are other factors to consider besides size. Here’s what we recommend taking into account alongside the correct size.

Weight

When choosing a bike helmet, consider weight. Some are very lightweight and feel like you are wearing nothing, while others can be quite heavy, making them uncomfortable. Light helmets weigh 150g to 250g, and heavy helmets weigh 300g to 500g.

Style

When picking the right helmet for the job, consider the type of helmet you want, whether it be a mountain bike helmet or a road bike helmet. Then, consider what it looks like and whether you like the way it looks.

Safety standard

Helmets need to meet the correct safety standards. Going with a good brand will ensure this. If you are looking at helmets that offer great specifications but are incredibly cheap, it’s good to check whether they are CPSC or EN 1078, depending on where you are.

Age and use

Helmets have a shelf life, and it’s important to check the age and use when buying. If the helmet is secondhand, we don’t recommend buying it, as if it has been crashed already, it is useless. Age: They only last a few years and less with lots of UV damage.

Special features

Finally, we have extra features. Some come with excellent extra protection systems, such as MIPS, and others have inbuilt lights. Consider these, as they can add much value to your riding experience.

Are you ready to buy that new bike helmet?

There’s no time like the present to start looking at a new helmet. Just make sure to measure your head beforehand and also go for the right helmet for you. With this article, you will now know how to measure a bike helmet. Check out buycycle for a bike to match your new helmet!

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