Bike Helmet Size Chart By Age of 2024

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Helmets are important for safety and their primary purpose is to protect your head from fractures and injuries in the event of a crash. It’s not enough to just buy a helmet, it is even more important to have a helmet that fits your head properly and does not in any way hinder your comfort. It mustn’t be heavy, and at the same it shouldn’t be too light as that may show a sign of inferior quality. Just somewhere around the middle where it is sturdy enough to withstand high impact without weigh you down.

Apart from the fact that a wrong sized helmet for you can hinder your comfort, if oversized, it can easily come off your head just when an accident is about to happen even if it’s well strapped to your head. More so, if it does not come off totally but hangs on probably your neck or thereabout, it could even result to serious injuries. Thus, the need for going for a helmet that fits you just right.

Size Chart

CategoriesAge GroupSizeHelmet
Toddler3-5XXXSmall (49-50cm)
XXSmall (51-52cm)
Joovy Noodle
Child5-8XXSmall (51-52cm)
XSmall (53-54cm)
Giro Scamp MIPS
Teen8-14Small (52-56cm)
Medium (55-59cm)
Thousand Heritage
Youth15-24Small (52-56cm)
Medium (55-59cm)
Large (58-62cm)
Smith Venture MIPS


25 and above
Small (52-56cm)
Medium (55-59cm)
Large (58-62cm)
XLarge (61-65cm)

Troy Lee Designs A2

The simplest and easiest way to quickly determine the ideal helmet size for you is to have an idea of your head measurement. Being informed of your head shape and size will give you an accurate idea of the size of helmet to go for in order to get the highest level of comfort and protection.

Identifying the Perfect Helmet Size

The are basically two ways to go about this. The first method involves wearing the helmet on your head and the second involves using your head dimensions to determine the size to go for. In order to measure your head size, you will need a tape measure, a note, and a pen.

With the help of the tape, take the measurement at the region having the fullest part of your head. More preferably, you can do this around the forehead region just a bit above your ears. That will help you to know the circumference of your head and where it is widest which is obviously at the forehead area.

With the pen and the note, record the sizes measured in both inches and centimeters. Afterwards, you check the size chart to see which of the helmets best fit your head.

Different Shapes of Head

Usually, head shapes which are used as standards for helmet designs are round, oval, and egg shapes.

  • Round: for this shape, the head is wider around the mid region in the temples area of the head.
  • Oval: it is referred to as ‘long oval’ shape. Out of the three shapes, oval shapes are the most common.
  • Egg: for this shape, it means the head is narrower at the bottom region and wider at the top.

On a general note, the shape of head often gets bigger as one grows. It is therefore possible to have helmet sizes categorized by age difference as a complementary identifier for which helmet size to go for. In this guide, we have chosen the best helmets out there in the market and suggested for each age group as you will find out as you read on. We of course know the hassle that comes with getting the best quality helmet apart from the need to worry about the size, but we have taken care of both. In fact, you will definitely find what you need here without having to search further again.

1. Joovy Noodle Helmet

Toddler ⇔ Age (3-5) ⇔ Size: XXXSmall (49 – 50cm), XXSmall (51 – 52cm)

The Joovy company takes protection many yards further with their incredible Joovy Noodle Helmet which is one of the best you can get for your 3-5-year-old toddler. It is very affordable and comes with features not found in most typical budget kid helmets. It is available in two sizes of small and medium with ranges 47-52cm and 52-56cm respectively. No matter the size of your toddler, you can be sure to get the right fit.

Ventilation was taken into consideration by the Joovy Noodle as it features fourteen (14) air vents that comes with built-in bug mesh in the anterior vents. This ensures that that there is sufficient air flow into the head of your kid so the head doesn’t feel too hot.

The visors have been improved for better protection and shielding. This helps prevent incoming objects or air mass from hitting the kid straight on the face. It also performs well in shielding the face from direct contact with the sun rays. It is also designed with nylon straps and pinch guard chin strap.

As your kids grows up, they grow in size also and with the adjustable dial of the helmet, you can easily fine-tune the right fit that makes them comfortable whenever they need to cruise. Just by turning left in order to loosen up or by turning right to tighten, you can keep the helmet functional as they grow up, hence no need to purchase another helmet.


  • Superior protection
  • Excellent ventilation
  • Very functional visor
  • Built-in bug mesh
  • Adjustable dial
  • Pinch guard, chin strap


  • The outer tape design peels off pretty quickly

2. Giro Scamp MIPS Helmet

Child ⇔ Age (5-8) ⇔ Size: XXSmall (51 – 52cm), XSmall (53 – 54cm)

The Giro Scamp MIPS is one of those you can’t have a hard time seeing anywhere: on a happy kid waiting to step on his strider for some nice chilly cruise, placed on a bike’s back, or dropped off aside a bike somewhere around the pump track. Then you start to wonder why Giro is so famous among kids? This is because it is very safe, comfortable and fits almost any child around this age range.

The Giro Scamp bike helmet is 8 inches high and comes 10 inches wide. It is designed with the Roc Loc Jr. fit mechanism with which you can easily fine-tune the vertical position and fine-tune the tension of the helmet. Essentially, the Roc Loc Jr. is a durable and simple dial fit system which has been carefully engineered to precisely fit the curvature and shape of a child’s head. The helmet has a large rubber-like knob for tension adjustment.

Talking about the structure, its in-mold construction combines with a durable polycarbonate external shell and with the shock-absorbing foam interior of the helmet. This construction allows for easy ventilation and makes the helmet cooler or comfortable to wear.

With it 8 vents, air flow is better improved. Suppose your kid has got a ponytail, the helmet allows her to wear without obstruction. It also features visor for protection and pinch-guard buckle for tightening and keeping the helmet in place.


  • Very durable
  • Solid in-mold construction
  • 8 vents
  • Ponytail compatible
  • Visor


  • Limited number of vent holes

3. Thousand Heritage Bike Helmet

Teen ⇔ Age (8-14) ⇔ Size: Small (52 – 56cm), Medium (55 – 59cm)

The Thousand Heritage Bike Helmet gives that kind of spark at first sight such that you just want to get it on your head. It’s of course dubbed as the ‘helmet you will want to wear’ by the makers. The helmet is lightweight and comes in style and grandeur.

This helmet is unisex, so it is well usable by both sex and is perfect for mountain biking, longboarding, skateboarding, scooters, and even road biking. It is designed with a PopLock system which provides a convenient way of locking the helmet with your bike. It is fitted just behind the logo mark and you can safely pop through your chain lock. It I the right type of helmet for teens who commute often or daily.

The Thousand Adult helmet features a dial fit system for seamless adjusting of the straps so as to get the perfect fit for you. Whether you feel like tightening it or loosening it up a bit, the dial fit will work just fine. Whether you are up for skateboarding or bike commuting or even recreational cycling, you can depend on the Thousand Adult Anti-Theft to keep you safe, it wouldn’t compromise your style!

It features a vegan leather straps made from animal skins and will keep you sweat-free and very comfortable. It is built with seven (7) vents and you can enjoy a sufficient amount of airflow around your head anytime you have this helmet on.

Another interesting feature of this helmet is its magnetic buckle. Seriously, you hardly have this coming wit even the high-end helmets in the market. With the magnetic buckle, you can easily fasten and lock the buckle in such that you don’t have to pinch your fingers at all.


  • Magnetic lock system
  • Leather straps
  • Amazing design and sturdy construction
  • PopLock system for anti-theft


  • Limited vents. Just seven (7)

4. Smith Venture MIPS Helmet

Youth ⇔ Age (15-24) ⇔ Size: Small (52 – 56cm), Medium (55 – 59cm), Large (58 – 62)

For youth bikers who love to take to the mountains and at the same time wants a helmet with a blend of style and fit, then the Smith Ventures MIPS is the one to go for. It is one of those helmets you can trust for protection, comfort and style. The level of ventilation here is superior, with the helmet coming with 20 optimized vents to allow smooth air flow.

The helmet is also cherished for being lightweight. It is designed with an in-mold construction which gives the helmet the study feel it has. It integrates an MIPS technology to provide a sliding layer between the external shell and the head thus enabling the helmet external shell to easily slide in a direction relative to the that of the head. This way, the force of rotation is greatly minimized.

You wouldn’t have a problem getting the best fit for you, thanks to the helmet’s adjustable VaporFit system. More interestingly is the helmets ability to wade off bacterial growth or odor on the inside as it has been designed with the X2 antibacterial action liner. With the super light webbing in the interior of the helmet, you enjoy some high dose of comfort as you cruise on all day long. It has a high-quality visor on the front which helps to prevent glare and ensure any rain or snow fall does not jeopardize your vision.


  • Quality visor
  • Anti-bacterial performance
  • Webbed inner lining
  • VaporFit system for quick fitting
  • Superior ventilation – 20 vents


  • Price on the high side
  • No magnetic lock

5. Troy Lee Designs A2 Helmet

Adult ⇔ Age (25 and above) ⇔ Size: Small (52 – 56cm), Medium (55 – 59cm), Large (58 – 62), XLarge (61 – 65)

If you are keen on getting a helmet with a fantastic performance, durable, comfortable and a touch of sporty look, search no further because the Troy Lee Designs A2 Helmet is the right deal. It’s a great helmet for adults and certainly brings a good value for money.  It is not heavy, does not compromise, and it is designed even for the harshest of crashes.

The Troy Lee helmet comes with a MIPS brain protection feature which is aimed at reducing rotational motion released to the head from angled impacts during crashes. Coupled with this is the combination of a double density EPS and EPP liner that offers maximum protection to the head against low and high impacts. Also, the shell is crafted from a reinforced polycarbonate which is a good addition for increasing the agility and sturdiness of the helmet.

Coming with large vents around the rear side of the helmet, you enjoy an appreciable level of ventilation around your head. The Troy Lee also features stabilizers fit system at the rear side for seamless adjustment of the fit. The visors are great and will hold well against flares, snow or rainfall.


  • Good quality visors
  • Adjustable fit system
  • Large vents
  • MIPS brain protection


  • The straps can easily hitch on the skin


When it comes to choosing helmets, the size is of premium importance and this cannot be overemphasized. With the industry constantly growing every day, it gets even easier for kids as little as 2 or 3-year-old to find their sizes. But finding the best not just for the kids alone, but for every members of the family can prove to be a hassle. With this guide (bike helmet sizes by age), you have the right kind of information needed to make a good choice. Make your pick and hurry to buy now!

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