Kids Bike Size Chart: The Definitive Guide to Kids Bike Sizing + Infographic

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Are you looking for the most accurate  kids bike size chart  available on the Internet (used by bike professionals around the world?)


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Then look no further, because this is the ultimate guide for you that wants to buy a (perfect) bike for your kid. 🚲

As any mother or father can testify, children don’t stay the same size for long.

That’s why choosing the right size bike for your kid can seem quite confusing.

Should you buy a bike that is too large for them at the start so they can ‘grow into it’ and have it for longer? Should you use a Kids Bike Size Chart? How high should the seat be and how much space should there be between the handlebars and the seat? How much stretch should there be in the leg and what size should the wheels be?

These are all good questions. But there’s surprisingly little information out there on the internet that deals with the question in a simple and informative way, let alone tell you which kids bike size chart you should use.

But don’t worry because is here to help. We’ve waded through the swamp of information and scoured our extensive research to give you the answers you need.

If you are in a hurry, check out all the bestselling kids bikes divided into age-groups:


One way to help choose a bike for your kid is to use wheel size to determine the right size bike. It’s not as comprehensive as the kids bike size chart below, but it’s a handy reference to have in mind. (Disclaimer: As Amazon Associates, we earn from qualifying purchases.)

Kids Bike Sizes Chart and Table

There are several factors that need to be considered when selecting a bike for a younger person. The first thing you should do is use our very own Kids Bike Size Chart to get an idea of what size of bike and what stage of bike you should be considering.

Wheel Size Age Height (inches) Height (cm) Bestseller Kids Bikes
10″ 2 2’09”-3’1″ 85-95 cm See bikes for 2-year-olds
12″ 3-4 3’1″-3’3″ 90-100 cm See bikes for 3-4-year-olds
14″ 4-5 3’3″-3’7″ 100-110 cm See bikes for 4-5-year-olds
16″ 5-6 3’7″-3’8″ 110-115 cm See bikes for 5-6-year-olds
18″ 6-8 3’7″-3’8″ 115-120 cm See bikes for 6-8-year-olds
20″ 9-11 4’0″-4’5″ 120-135 cm See bikes for 9-12-year-olds
24″ 11-14 4’5″-4’9″ 135-145 cm See bikes for 11-14-year-olds
26″ 15+ 5″+ 145+ cm See bikes for 15-year-olds +

The important things to ensure as well is that the child looks and (very importantly) feels comfortable on the bike. Secondly, it’s a good idea to make sure the kid thinks the bike is cool and that they really, really like it.

Child riding bike - correct size

A more accurate kids bike size chart (using the inseam)

Another useful form of kids bike size chart for determining the right size of bike, and some might say more accurate, is the inside leg length (or inseam) approach.

Kids inseam bike sizing

Measure your kids inseam by following these 3 simple steps:
  1. Place your child with his back against the wall and spread their feet 3-4″ apart.
  2. Place a book between his legs – spine up. Raise it until snug against his crotch (this mimics your bike seat).
  3. Now measure from the top of the book (spine) down to the floor.
Wheel Size Age Inseam (inches) Inseam (cm) Bestseller Kids Bikes
10″ 2 12″-14″ 30-35 cm See bikes for 2-year-olds
12″ 3-4 14″-17″ 35-42 cm See bikes for 3-4-year-olds
14″ 4-5 16″-20″ 40-50 cm See bikes for 4-5-year-olds
16″ 5-6 18″-22″ 45-55 cm See bikes for 5-6-year-olds
18″ 6-8 20″-24″ 50-60 cm See bikes for 6-8-year-olds
20″ 9-11 22″-25″ 55-62 cm See bikes for 9-12-year-olds
24″ 11-14 24″-28″ 60-72 cm See bikes for 11-14-year-olds
26″ 15+ 28″+ 72+ cm See bikes for 15-year-olds +

Buying your boy or girl a bike isn’t as simple as it was in the old days

At least not as simple as it was for me. When it came to my parents choosing the perfect bike for me it came down to which one of my brothers’ old bikes I wanted out of the garage. Having chosen, my father would lift the bike down off the peg, made sure it wouldn’t fall apart, and then said I had to be home before dark.

It’s different for kids these days

As grownups the ‘proper’ way to choose a bike is by primarily referencing ourselves to the frame size of the bike we intend to choose. In the most basic of terms, if we can stand over the bike with our feet planted on either side of the upper tube, then we can say with some certainty the bike fits.  This is not how you choose the right size bike for your boy or girl. Ideally you should use a kids bike size chart to make sure you are making the most informed choice possible.

Fortunately, there are guides and guidelines for helping you choose a bike that is perfect for your child’s age and size. Take a look at the infographic below.

Infographic: Everything you need to know about kids bike sizing

The general rule of thumb is to use a bike size chart for kids. Sizing charts are available from all good bike websites and stores. There are slight variations in some of them, especially when moving to adult sizing charts, but for children they do remain consistent.

Below is our very own bike size chart for kids that puts all the latest thinking, science and experience to make it easier for you to pick the perfect size bike for your kid. The information within the guide contains the same information that bike mechanics and professionals use around the world to size bikes for kids and can be used as a really good guide for the rest of us.


Kids bike size chart

As the kid’s bike size chart above clearly shows, when it comes to kids bikes, there are 4 main things to focus on.

They are:

  • Child’s age
  • Height
  • Inseam
  • Wheel Diameter­­­­­­­­­­­­­­­­­­­­­­­­­

The child’s age determines a lot. If we take a minute to look at our snazzy infographic above, then we see that for beginners and younger kids between 2-4 years, a balance or toddler bike is a good starting point. Balance bikes are a great way to introduce children to the concept of cycling without the need for complicated pedals or a fully developed sense of balance. Normally children ride them with their feet on the ground and develop to do daring small glides.

Not everyone has the advantage of having a balance bike as an infant though, and it’s still totally acceptable to only start learning to ride between 4 and 6 years of age. One can learn how to ride a bike at any age. But between 4 – 6 years of age, almost all kids’ bikes will have pedals on them. A bike with training wheels or stabilizers (same thing) is a good choice of bike. Don’t limit your choice to just bikes with training wheels though, as training wheels can be bought separately and be installed or removed with ease.

Training wheels help children find their sense of balance on a bike and help avoid unnecessary falls and bumps. However, many pick balance bikes instead of training wheels. Read more about training wheels vs. balance bikes here.

From 6 to 8 years of age and up, the other elements of bike sizing start to have more importance.

A Quick Note About Height

Kids heights should always be considered as they are a better indicator of a well fitted bike than age alone. For instance, not all 11-14-year olds are going to be between 115-120 cm tall. Some will be shorter, and some will be a lot taller. It makes sense then to use height as an important factor when buying a kid’s bike.

In the same way that height is a major determiner in choosing the right bike size for kids, the inseam of your child’s leg measurement is also another key factor. Just because your kid is 130 cm tall doesn’t mean that their inside leg measurements will correspond with a leg length of 50-60 cm. In this case, it’s best to physically determine which bike and what seat and handlebar adjustments/positions are most comfortable.

Wheel size determines the proportions for the rest of the bike when it comes to kids. As a baseline average, almost all kids wheel sizes are generally made with either 12, 16, 20 or 24 diameters. And just so you know, by the time you reach a 26-inch wheel you are crossing over into the standard sized adult bike wheel size. While these days most mountain bike wheels come in either 27.5- or 29-inches, for years a 26-inch wheel was the standard size. (Which is a throwback to the early years of mountain biking.)

As a rough approximation 10-12-inch wheels are designed for kids starting off biking and who on average are aged between 3-5 years. By the time your child is 14 years old, you will mostly be looking at 24-inch wheels.

What size bike at what age:

Use our handy kids bike size chart infographic guide to determine the right size bike for your kid’s height, leg measurement and appropriate wheel size, and you won’t go far wrong. If you want to know more though, read on:

2 – 4 Years 

Smaller kids could face difficulty using a standard bike when taking up cycling for the first time, especially if there are gears, brakes and other adult style bells and whistles. So, as I said above, a balance or toddler bike is a good option when starting out, especially for riding around inside, under adult care and building confidence. Look for bikes with wheel diameters of approximately 10-12 inches.

Balance bikes are exactly what they say they are. They have no pedals and tend to only have a back brake if any at all. They are brilliant for letting your kid develop their sense of inertia, balance and learning how to steer. And as they have no means of propulsion other than how fast kids can push their feet off the ground, they are relatively safe to use indoors, and a generally safe way to learn overall.

5-8 Years

As kids grow up and their confidence, skill, and sense of adventure grow, they can move to the larger 14 – 18-inch wheels. Kids bikes at this age start to feel and resemble grown up bikes. It’s also where the breadth of choice also really starts to increase, and it can start to feel somewhat overwhelming trying to choose the right bike for your kid. Don’t panic though, and keep the sizing chart in mind when selecting.

These are your classic first ‘proper’ bike models. Bikes in this range do come with simple gear sets and basic front fork suspension, but my advice to you is not to bother with either the gears or the suspension.  They will most likely be cheaply made, not very good and add more weight than you child needs. That will also depend on how much you want to spend as well, of course.

The most important factor here is the fit, as discussed above. Make sure the kids’ feet can easily touch the ground and their hands can reach the brakes on the handlebars. This is where, in my experience, riders are born or broken. Unlike balance bikes, their feet will be on the pedals, not trailing along the ground for extra stability. They will also be going faster. What this means is they are now at a stage where they are more likely to have the occasional accident. Kids can deal with the occasional accident, but not if it becomes a familiar occurrence. So, make sure you buy the right size.

9 -15 Years and up

The older the kid, the bigger the wheel. Fortunately, wheel sizes on bikes for children don’t really get much bigger than 20-26 inches, and in the upper teen years kids also tend to stop growing.

Just because your kid is growing up the same rules still apply, however. For some kids especially the larger and taller ones, some adult bikes could seem like an attractive proposition, just be careful not to jump the shark too soon. All the above advice still stands. Make sure riding positions are comfortable and that you are not buying a bike with wheels that are too large.

No matter the age of the kid you are buying a bike for, make sure the bike fits the child and you are not trying to get the kid to fit the bike.

This is where most kids are likely to come face to face with proper set of gears and suspension. Geared versions of these bikes will come with between 5 and 10 gears, with hill climbing firmly in mind as opposed to speed. While not a necessity, it is handy for getting children used to how gears work. As a youngster, I rode BMXs up to the age of 16. However, a lot has changed since the early 21st Century. And while things were of course supremely better back in the day, the biking world has moved on.

It’s not uncommon now to find bikes in this age range 36 gears and triple chain sets. In my humble biased opinion, these additions just add extra weight, are more complicated and are not worth the extra money at this level. If you can, let your kid be a kid just that little bit longer. If they insist on gears, then try to limit them to single or low digit gearing.

Now yes, all that gearing, and suspension does look cool, especially if you’re a kid, but the chances are the forks will be cheap, heavy and not actually be effective. The truth is that fully rigid bikes at this level will not only be lighter, but also higher quality. If your kid is insisting on forks, then either buy the lightest frame possible, or upgrade to some 3rd party suspension forks. It will be money well spent.

Height charts: Not the Definitive Factor?

With all that said, height charts are not the single definitive factor when it comes to picking your kid’s bike. Instead, think of them as more of a starting point to help give you an idea of the size of bike you need and want for your child.

By far, the most important thing to do is get a test ride and observe how well your child is able to ride. It should be easy and in a controlled manner. You must consider the proportions of the child’s body and personal riding disposition.

Make Sure the Kid Likes the Bike

It’s probably not a good idea to spend money on a bike the young one clearly doesn’t like with the hope they’ll change their minds at some future date. They might change their mind, but then they might not, and Children’s bikes are not great for hanging or washing on. I’ve tried, it doesn’t work; not well anyway. There’s a chance the bike will end up unused and pristine under the stairs or gathering dust in the garage.

Don’t scar your child emotionally for life by buying them a Destructor 4000 Extreme when what they wanted was the Princess bike with a basket and sparkles. I’ve been there, done that and the results are not pretty.

Nice bike for kid

And if you buy a bike that is too small your child, they may feel silly sitting on it, and even feel cramped. Conversely, buying a bike that is too large will be unwieldy, difficult to control, and undermine their fledgling confidence on the pedals.

Be under no illusion, the whole thing is a minefield, but a minefield you can cross.

The good news is that kids have so many choices when it comes to bikes. From teenagers to toddlers, there’s a bike for your child.

The bike should fit the child, not the other way around.

Safety is also a paramount concern and you should make sure to consider the following things when buying a bike:

  • Never buy a bike that is too large for your child in the hope that ‘they will grow into it.’ Follow the guidelines in our kids bike size chart.
  • Your child should be able to straddle the middle of the bike with their feet flat on the ground on either side of the bike with a good inch or two of clearance. They should not have to lean the bike one way or the other to get a foot flat down on the ground.
  • You must consider what happens if they suddenly need to hop off the bike quickly. This is especially true if your kid is a boy and you think you might like grandchildren one day. The bike should only have a slight lean when your kid puts their bottom onto the seat, puts one foot on the pedal, and then scoots away.
  • Your child, or the child you are buying the bike for, should be seated in a mostly upright position, and their knees and legs should not be bouncing of the handlebars. On the other hand, their legs also should not be completely stretched out at the lowest vertical position of the pedals either. There should always be a slight bend in the leg.
  • Children should also be able to turn the handlebars in a sweeping motion to their full extent without being overstretched. Younger children tend to use the turning arc of the handlebars to steer more than older children and adults, who will also use balance to negotiate turns and corners.
  • Ensure the brakes work.
  • Make sure the kid knows how to work the brakes.
  • Ensure the kid know the difference between the front brake and the back brake. Pulling on a front brake hard at a high speed can cause a child to be launched like a rocket over the handlebars, so
  • Wear a helmet.

Expert Advice Is Invaluable

Never ever underestimate the power of good advice given by an expert. 5 minutes with an experienced and reputable bike expert can save you hours spent scouting the internet for the answer.

Bicycle mechanic

Why do some kids’ bikes seem to weigh as much as my own adult bike?

That’s a good question.

It used to be that kids’ bikes would be the only thing a Twister in Missouri would leave behind. The cheap ones still are and that’s because they tend to be made from steel rather than aluminum. There are advantages of heavier steel bikes in that they are rather indestructible, but they can also take a real effort for kids to ride, especially up hill.

More commonly these days, most quality bike manufacturers offer decent value lightweight bikes for the younger rider. This is an important fact to be aware of as proportionally speaking, kids’ bikes are harder to pedal than adult bikes anyway due to the smaller wheelbase. So, if you can, do try to buy light as you can.

You should also be aware that most kid’s bikes are designed to withstand a certain amount of abuse and rough play but that doesn’t mean they don’t need some looking after every once in a while.

Is there a difference between bikes for girls or boys?


Or at least there shouldn’t be, especially for the younger rider.

Admittedly as kids get older, certain anatomical differences will start to assert themselves but even then, that’s not something that needs to concern any parent until their kids reach their late teens.

That said, people still market bikes that are specifically for either girls or boys. Most notably, the difference between these girls’ and boys’ bikes tends to be the ‘lower’ stand over -Murder She Wrote/Miss Marple- style bikes made for girls.

(For some reason, they also tend to have baskets. I say, ‘for some reason,’ but I have just been informed by my oldest daughter (9) that the basket is very useful for transporting Barbies and snacks. I tried telling her this is why we have panniers and backpacks, but she just won’t listen to reason. I’m still convinced that the reason she picked the pink beach-cruiser style ‘thing’ she rides everywhere was because it was the only bike in the shop that had streamers stuck onto the handlebars. Go figure.)

But yes, specific girls’ bike also tend to be brightly colored with classic feminine pink and white etc. Conversely, specific boys’ bikes will classically cliche darker blues and bright reds.

What’s singularly important to note at this point however is that there is no physical need whatsoever for the lower tube for girls and higher tube for boys’ difference.

The original idea behind the lower top tube bike designed for girls and ladies is something of a throwback to the 1800s origin of the modern bicycle itself, and a time when the female of the species was considered to be a ‘fragile’ ‘delicate’ damsel of a thing compared to the far ‘superior’ ‘bigger brained’ male. Females also had to consider their modesty when cycling, and the idea that they would have to ‘mount’ a bicycle by raising their legs over a high physical upper bar was tantamount to a scandal and may cause episodes of fainting. Women also tended to wear big dresses and long skirts back then as well and this meant having a high-top tube was somewhat impractical.

Father and son biking

Mountain bike or Road bike for the older kid? Does it matter?

I think to be fair, there’s not really much of a style choice in the younger cyclists’ arena. A large swathe of kids bikes right up to the 24-inch wheel sizes, almost uniformly resemble the mountain bike or regular style with the wide, grippy tires and horizontal handlebars.

The first real differentiation between bike styles starts to creep in at 24-inch wheelbase level. This is where you will start to see the option to buy slick tired bikes with the racing bike drop handlebars. But as always, really, it all comes down to what your kid wants to ride.

I don’t think I can give a lot of advice on this particular aspect of riding as it’s really a personal choice. I would stick with the mountain bike style though if the kid you are buying for doesn’t express a strong opinion. It’s still possible at this stage of the game to own a fully functional kids’ bike that will do the job.

That said, if all they do is ride on roads, and never go off road, then perhaps a road bike is the way forward. Whatever you do, make sure they try them out first.

What about a BMX?

BMX style bikes have an awful lot going for them. They are tough, single geared, extremely durable, and their resale value is quite high.

The best thing about BMX style bikes though is their inherent ability to go anywhere and deal with any biking situation life can throw at them. By their nature, they are small wheeled bikes, which means, as I’ve already stated, kids can start using them at a very young age, and many kids’ versions will come with a 12-inch wheel.

Even when moving to a fully sized 20-inch wheel BMX base, the bike is the same shape, just slightly bigger. One of the big pluses of a BMX is that for the same money as a kids’ mountain bike, you’ll probably end up with a lighter and better bike overall.

Helmets and Children: A Word to The Wise!

It is essential that whenever a kid is riding a bike they wear a properly fitted helmet that is the right size and weight for their head. Children’s heads tend to be marginally larger in terms of proportion to the rest of their bodies.  Do not underestimate the health and safety benefits of wearing a bike helmet. Do not overlook the importance of your kid’s brain. It is a sad truism that a lot of time is spent picking the perfect bike while the purchase of a helmet is an afterthought or is bought based on the style or color of the helmet.  Do not let this be you.

It might also be a worthwhile investment to buy some elbow and knee pads, especially when they’re just learning.

Final thoughts on Kids Bike Sizes

  • Get the right size at the right time.
  • Make sure the bike fits.
  • Use our kids bike size chart, but remember they are only guidelines.
  • Make sure they look comfortable on the bike.
  • Ensure the kid wants the bike you’re buying.
  • Buy the best you can afford, but be cautious with your cash- stay on budget.
  • Don’t bother with all the bells, whistles and heavy fancy gadgets bolted on to appeal to easily influenced minds.
  • Do get expert advice.
  • Do some research first so you can at least understand what the expert is talking about.

Really final thoughts

Be responsible and teach your kid how to be safe when they ride, wherever they ride.


Kids bike helmet

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