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Kids and Toddler Bike Helmets: How to Choose

From Size and Fit to Safety Technology, We Guide You Through the Features that Really Matter

Each year in the United States, about half a million kids are seriously injured in bicycle-related accidents.   In most cases, a properly fitted helmet could have eliminated or minimized head injuries sustained during the accident.  Unfortunately, many parents underestimate the importance of helmet fit and other safety features, and too often shop by color or style.  That’s where we come in! With 9 years of testing, parenting and bike industry trade shows under our belts, we’re here to help you get informed and find the best and safest helmet for your child. The 8 main features to look for when shopping for a kid’s helmet are: 1) size, 2) adjustability, 3) use , 4) construction, 5) buckle type, 6) visors, 7) MIPS safety technology and 8) CPSC/ASTM certifications.

For a quick look at our top ranked helmets, check out our 10 Best Kids’ Helmets list. 

Kids Bike Helmet Sizing and Buying Guide graphic showing all the different features of bike helmets that need to be considered for purchase


1.  How do Kids Bike Helmet Sizes Work?

Kids bike helmet sizes are generally broken down into three categories – toddler, child, and youth. These categories are broad and only give you a rough idea of whether or not a helmet will fit your child’s head. Helmet sizing really comes down to your child’s head circumference.

Kids Helmet Size Examples - 50th Percentile

Approx. AgeGirl Head Size (cm)Boy Head Size (cm)ExampleExample
12 mo.
18 mo.
2 yr.
Giro Scamp w/ MIPSgiro scamp kids' bike helmet - blue
2.5 yr.
3 yr.
3.5 yr.
Joovy NoodleJoovy Noodle Helmet in red
4 yr.
4.5 yr.
5 yr.
Bell Sidetrackbell sidetrack youth bike helmet - green
6 yr.
7 yr.
8 yr.
Giro Tremorgiro tremor mips kids' bike helmet - black green

Kids bike helmets are definitely not one-side-fits-all. As an example, the Giro Scamp comes in two sizes for toddlers and pre-schoolers. XS, which fits heads with a circumference of 45 to 49 cm, and S, which fits heads with a circumference of 49 to 53 cm. The very popular Joovy Noodle is also made for toddlers and pre-schoolers, but its smallest size starts at 47 cm and can fit heads up to 52 cm.

Joovy Noodle vs Giro Scamp toddler bike helmets. The rear of the Noodle is pointy, while the Scamp is flat.

Bike helmets can fit a range of head sizes because their internal cages can be tightened or loosened to fit snuggly on a child’s head. Kids helmets are generally designed to fit a wider range of head circumferences than adult helmets, giving a child plenty of room to grow so you don’t have to buy a new helmet too often.

In summary, it’s less about whether your child is a “child” or “youth”, and all about what their head circumference measurement is. As a result, it’s absolutely necessary for you to measure your child’s head before you buy a helmet!

To measure your child’s head, use a soft tape measure and measure the circumference of their head one inch above their eyebrows (the thickest part of their head). Find a helmet that includes this number in its size range.

Collage of four children. First child shows how to measure the circumference of a head properly with a tape measure, 2nd child has a properly fitted helmet, 3rd child has a helmet that is too small, and 4th child has a helmet that is too big.

Helmets Shown: Specialized Sierra, Uvex Quatro Junior, Nutcase Little Nutty.

If you are unable to measure your child’s head, use the 50th percentile head circumference chart shown above as a rough estimation.

Once I have the right size helmet, how should it actually fit on my child’s head?

We have a great infographic that provides 6 easy steps to fitting and adjusting your child’s bike helmet. Adjusting your child’s helmet to ensure a proper fit is just as essential as making sure your child is wearing one.  A poorly adjusted helmet can fall off or move around, greatly reducing the helmet’s ability to offer protection during a crash.

CLICK HERE FOR OUR HELMET FIT GUIDE: How to Fit and Adjust A Child’s Bike Helmet!

Read the next section on Adjustability for more about the features that allow you to properly adjust your child’s helmet.

2. Adjustability

Helmet Internal Adjust Systems

To provide a proper fit, many helmets have an internal plastic cage that can adjust to fit the head of the child.  Some helmets, generally lower-end, offer no internal adjust systems.  Since the head shapes of children vary greatly, internal adjust systems allow the helmet to conform to heads of all sizes, helping the helmet stay in place and better protect the child.  Various types of internal adjust systems are available on child and youth helmets.

The three main types of adjustment systems in helmets are: Dial adjust in which you turn a knob to adjust the fit, Pad Width Adjust in which you choose to insert pads of various thickness, and Lazer's Autofit that uses tension wires to auto-adjust to the head

Helmets Shown: Melon, Giro Dime and Lazer Nut’z

Traditional Dial-Adjust: The most common adjust system is a dial located in the back of the helmet.  By turning the dial, the internal cage adjusts to fit a child’s head.  Helmets are limited in the amount they can adjust, so it is still vital to purchase the correct size. Traditional dial-adjust systems can be found on most high-end helmets, including all high-end Giro and Bell helmets, as well as Nutcase and Melon (shown above).

Pads Width Adjust: Most skater-style helmets and low-end bicycle style helmets do not come with an adjustment system, but rather different pads of varying thickness.  Prior to wearing the helmet, parents are required to insert the thickness of pad necessary to achieve a snug fit.  Unfortunately, many parents fail to adjust the helmet, thereby leading to a poorly fit helmet that rarely stays in place.  Furthermore, re-adjusting the pads as a child grows is rarely taken into consideration or the thinner sized pads are lost, and as a result, pad-adjusted helmets can be more challenging to fit correctly.  The Giro Dime, shown above, is one of the few pad-adjusted helmets that we recommend.

Lazer Self-Adjust: Lazer’s unique Autofit system automatically adjusts to fit the wearer’s head.  The system adjusts via a tension wire, encased in plastic housing, that allow the internal cage to stretch to fit a child’s head.  Always producing a proper fit, the Autofit system is ideal as it ensures that a child’s helmet is properly fitted, even when the child puts it on themselves.  The Lazer Nut’z and P’Nut both have the Autofit system.

Strap Sliders

In addition to the internal-adjust system of a helmet, the chin strap and strap sliders play an important role in keeping a helmet squarely on a child’s head.  To prevent the helmet from tilting forward or back, the chin straps on a helmet should come to a “V” right below the child’s ear.  Plastic sliders hold the straps together, allowing them to continue together to the buckle.  If not properly placed below the ear, the helmet is much more likely to fall forward or back on a child’s head.

Locking sliders found on many high-end brands, such as the Lazer Nut’z (shown below), lock into place, helping to maintain the proper “V” below the ear.  Most helmets, however, do not have locking sliders, which requires the chin straps to continually be adjusted.  This is especially problematic with standard (non-angled) sliders as they easily slip out of place, especially when kids carry their helmets by the chin strap.

Collage showing slider adjustment on helmet straps. Locking sliders (unlocked and locked), Angled Non-locking, and standard non-locking


 3. Use

Standard Bike Helmets vs. Multi-Sport Skater Style

Skater-style and standard bicycle helmets each have their pros and cons. Traditional bicycle helmets are lighter, have more vents and are more adjustable, but are not dual-certified and can be harder to fit odd-shaped heads. Skater-style helmets are generally heavy, lack a visor, have less vents and are less likely to have dial-in adjustments, but they also offer more coverage, can be dual-certified and tend to fit odd-sized heads better.

Traditional vs. Skater-Style Helmets

Traditional Bike HelmetSkater-Style Helmet
Best For: Kids who mainly ride bicycles, especially those in hot climatesBest For: Kids who regularly ride bikes and scooters or skateboards
LightweightMore coverage
Well-ventilatedMany are dual certified for bike & skate use
Generally more adjustableMore style options
Limited style optionsLess vents, more sweat
Less coverage on lower back of headHeavier, less likely to stay in place
Limited visor options

Toddler Helmets: Flat Back for Trailers and Child Bike Seats

If you plan on riding with your kids in a trailer or bike seat, a helmet with a flat, smooth back will help to prevent it from sliding forward during a ride.  The Baby Nutty and Lazer Bob are certified for ages 1+ and have a flattened back to prevent a child’s head from being pushed forward in a trailer or seat.

Helmets with Flat Backs for Child Bike Seat or Trailer Use

The WOOM by Melon and Nutcase Baby Nutty helmets have flat backs for use in a child bike seat or in a trailer. The Laser P'Nut and Joovy Noodle helmets do not have flat backs and are not ideal for use in a bike seat or trailer.


4.  Construction

There are two main types of helmet construction – in-mold and hardshell.  Both types of construction provide adequate protection in a crash but vary in durability, the number of vents, and style. The main difference between the two types is how the outer plastic protective shell is adhered to the foam core of the helmet.

In-Mold: The outer plastic shell and the inner foam core are fused together with in-mold helmets.  The fusing process allows for more vents and typically provides for lighter overall weight.  The outer plastic shell of the helmet will never crack or come off as it is fused to the foam core.  Due to their thinner plastic shell, in-mold helmets cannot be certified for skateboard use by ASTM standards. As a result, essentially all higher-end traditional bike helmets are built with in-mold construction, while very few skater-style helmets are.  Melon helmets, however, are made with in-mold construction, which is why they are lighter than most skate helmets and why they are not certified for skateboard use in the US.

Hardshell: There are two main types of hardshell helmets – skater-style and lower-end bicycle helmets. On skater-style helmets, a thick plastic shell is glued to the foam core of the helmet.  The thick shell allows for increased durability, multiple impacts for skateboarders, and is required for ASTM skateboarding certification. On lower-end hardshell helmets, a thin plastic shell is taped onto the foam core.  These thin shells easily warp, crack, come off, and offer little durability.

Helmet Construction Examples

In-Mold ConstructionSkater-Style HardshellLower-End Hardshell

Giro Raze

Nutcase Street

Giro Rodeo

 5.  Buckle Type

A buckle may not seem like a big deal, but kids that get pinched while trying to fasten a helmet are hesitant to wear them, often leading to unwanted battles with parents.  To prevent pinching, several different companies have developed “pinch-free” buckles.  Standard non-pinch buckles consist of a plastic guard underneath the buckle.  More advanced systems include the magnetic Fidlock® buckles found on Lazer, Nutcase and Melon helmets as well as Uvex‘s unique ratcheting buckle.

Collage showing various types of helmet buckles: standard, non-pinch, Magnetic Fidlock, and Uvex Ratcheting Buckle.

6.  Visors

Keeping the sun out of kids’ eyes will certainly make for a more appealing ride.  Most traditional bike helmets have built-in or clip-on visors while most skater-style helmets have no visor.  Built-in visors are common on pre-school helmets as they provide much-needed protection to the face in the event of a face plant.  Helmets for youth generally have snap-on visors that are merely for looks and/or limited sun protection.  A few skater-style helmets, such as Nutcase, offer small visors.



MIPS is an additional safety feature offered on several high-end helmets. MIPS stands for Multi-directional Impact Protection System and allows the energy from the crash impact to be absorbed by the helmet regardless of what direction the impact is coming from.  Studies have shown that MIPS can decrease brain injury by 30%.  The system consists of a non-obstrusive inner plastic cage that is attached to the foam core with flexible rubber anchors.  Upon impact, the anchors stretch, allowing the foam core to rotate around the child’s head. MIPS is available on the Lazer P’Nut and Nutz and the Giro Scamp (Toddler), Dime (youth skater-style) and Tremor and Hale.

Collage showing the internal plastic shell and yellow anchors that make up the MIPS safety technology system.

  • 8. CSPC/ASTM Safety Certifications

    All helmets sold in the US must comply with CPSC (Consumer Product Safety Commission) standards and be labeled with a sticker.  All bike helmets sold in the US are therefore “safe” in terms of providing protection, but only if they are properly fitted and adjusted to a child’s head.  Higher-end helmets tend to offer a better fit and stay in place more securely than low-end helmets, which is why we believe they usually offer better overall protection.

    Helmets are certified for specific sports and should only be used for those activities.   All helmets that are CPSC certified for kids biking are also certified for in-line skating and scooters (including low-speed, motor assisted).  BMX riding and downhill mountain biking require a separate level of certification beyond the standard CPSC kid’s biking certificate.  All certified helmets are required to be labeled with a CPSC sticker.  The CPSC does not have a standard sticker, so they vary from helmet to helmet.

    As a word of caution, when buying a helmet online, be sure to buy from a reputable company that is an authorized to sell branded helmets as counterfeits helmets are starting to become a problem.  All companies we link to are certified sellers (with the exception to 3rd party sellers on Amazon, which Amazon claims to check).


    For babies, toddlers, kids, and youth,  CPSC certifies helmets for biking in two age categories – ages 1+ (Persons Age 1 and Older) and 5+ (Persons Age 5 and Older).

    1+ Certifications are for really small toddler/ 12mo+ baby helmets (16 CFR 1203).  They offer more coverage than the 5+ helmets, but generally max out at 50 cm head circumference and are too small for many toddlers and pre-schoolers.

    5+ Certification: The classification for “Persons Age 5 and Older” is confusing. Many 3 and 4 year-olds’ (and some 2 year-olds’!) heads are too big for the 1+ classification helmets and must use a 5+ certified helmet.  This is normal and completely safe. There is not an age-based certification level above 5+.  As a result, the 5+ certification will apply for all youth helmets as well.

    Example of a CPSC certification sticker found in a helmet.



    ASTM certification is for helmets used for skateboarding and trick roller skating. Skateboarders crash more often and in different ways, so different safety standards are required than for biking.  In Europe, the EN standard is used instead of the ASTM standard for skate certification.  The EN standard is NOT as rigorous as the ASTM.  There are several European brand helmets sold in the US as “dual-certified” as they meet the EN standard, but they do NOT meet the more rigorous ASTM standard in the US.  When shopping for a helmet to be used as a bike helmet and a skateboard helmet, be sure it is CSPC certified as well as ASTM certified for skateboarding.  BMX and downhill mountain biking have additional ASTM (International Safety Standards) they must meet in order to be sold specifically as such.  Additional information about CPSC standards can be found here.

    Example of ASTM, CSPS, and CE certification stickers found in the helmet.

    Related Articles

    Kids’ Helmets: Product Filter Tool – To view and filter baby, toddler, and kids’ helmets, and read reviews.

    10 Best Baby/Toddler Helmets: Our fast and easy list for the littlest noggins.

    10 Best Kid’s Helmets: Our fast and easy top picks list.


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