How To Size A Kids Bike: A Complete Guide (With Kids Bike Size Chart)

Choosing the right bike for your child involves more than just picking the coolest and most colorful one in the bike shop.

As parents, our main priorities for our kids are health, safety, and enjoyment.

With this in mind, you need to make sure your child’s bike fits them properly. If their bike doesn’t fit them, it could not only be dangerous, but it could also make the experience miserable and put them off riding altogether.

So it’s critical that you know how to size a kids bike before buying one. When it comes to sizing a kid’s bike, there are a few factors you need to consider.

In this article, we’ll be covering:

  • How To Measure Bike Size For Kids
  • Kids Bike Size Chart
  • Trying A Bike Out For Size
  • Types Of Kids Bikes Based On Age And Wheel Size
  • Buying A Bike Based On Ability And Maturity

Let’s go into the details on how to size a kids bike!

How To Size A Kids Bike: Title Image

How To Measure Bike Size For Kids

You need a starting point to determine the correct sized bike for your child. Therefore, you need to measure them before referring to the kids’ bike size chart.

It is straightforward to measure your child for a bike as you only need two measurements: their inseam and their height.

Here is how to measure bike size for kids in three steps:

1. Have your child stand against a wall with their feet shoulder-width apart while wearing shoes.

2. For extra accuracy, place a book between their legs at the top of the crotch area. This ensures that you’re not just measuring up to their trousers.

3. Measure the distance from the ground to the top of the book. This will give you their inseam measurement to compare against the kids bike size chart.

Four kids ride their bikes on a dirt path through a field.

Kids Bike Size Chart

Now you have your child’s inseam, you can use a kids bike size chart to ensure you choose a bike that fits them correctly. We’ve built a super simple kids bike size chart below.

The kids bike size chart uses your child’s height and inseam to determine what size bike they need. You need to cross-reference the inseam measurement and their height with the chart.

But, you also need to ensure that you choose a bike with the appropriate wheel size and features for their size and age group. We’ll come to this shortly.

When you look into how to size a kids bike, it varies from sizing an adult’s bike. Kids bikes also use wheel diameter, while adult bikes use the frame size and seat height.

You can expect to see kids bikes with wheel sizes ranging from 12″ to 24″. Adult bike wheels usually start at 26″, unless it is a compact commuter or another specialist bike.

Wheel SizeAgeHeightInseam
12″2 -32’10” to 3’4″14-17″ (35-42 cm)
14″3-43’1″ to 3’7″16-20″ (40-50 cm)
16″4-53’7″ to 4’0″18-22″ (45-55 cm)
18″5-63’9″ to 4’3″20-24″ (50-60 cm)
20″5-84’0″ to 4’5″22-25″ (55-63 cm)
24″7- 114’5″ to 4’9″24-28″ (60-72 cm)
Kids Bike Size Chart

Trying A Bike Out For Size

Once you have established a starting point using the kids bike size chart, it’s time to try some out for size.

Get your child to sit on the bike’s saddle while holding the handlebars. When it comes to a balance bike or their first pedal bike, they should be able to put the balls of their feet on the ground without any problem.

If you are shopping for their second pedal bike, they should be on their tiptoes when on the saddle.

They should also be able to stand straddling the bike with a 1″ to 2″ gap between their crotch and the bike’s top tube.

If everything seems in order, it’s time for a test ride. Ensure that there is a safe place to ride the bike and that your child is wearing a helmet.

A test ride is the perfect way to see how well the bike fits them. You will see how well your kid can balance on it and how comfortable they are riding.

The test ride should involve pedaling, steering, and braking. If they can do all of these things confidently for their ability, you have found the right bike for them.

It’s worth trying out a few different models to create a shortlist. Your child can pick which bike feels best for them. However, they’re probably more likely to choose the coolest looking one!

A girl rides her bike across a grassy hillside.

Types Of Kids Bikes Based On Age And Wheel Size

Balance Bikes

Balance bikes are built for children between 2 and 4 years old. These first two-wheeled bikes come with 12″ wheels and have no pedals, and often no brakes. The child scoots the bike forwards using their feet and stops by planting their feet on the ground.

Balance bikes are excellent for building your child’s confidence and giving them their first taste of independence. They also go a long way to build the foundations they need for balance.

Many parents turn to balance bikes rather than fitting regular bikes with stabilizers or tricycles. This is because kids can become reliant on stabilizers, hindering their progress.

Small Wheelers

After the balance bike, your child will progress to a small wheeler. These are suitable for kids between 3 and 5 years old and are the first bike they will ride with pedals.

These bikes have features and characteristics you will find on adult bikes. For example, they have brakes, pedals, and freewheel hubs. However, at this early stage from transitioning from a balance bike, it’s best to keep things simple.

Try to avoid bikes that are complicated to use. Single-speed bikes with coaster brakes are better until your child has developed some coordination and dexterity.

Small wheel bikes usually have 14″ wheels, but you will also come across many with 12″ to 16″ wheels. You need to choose the right-sized wheels to get the proper fit.

16″ Wheelers

The next size up from small wheelers on the kids bike size chart is bikes with 16″ wheels. These are suitable for kids aged from 4 to 6 years old.

Kids bikes in the middle sizes usually come with brakes with proper brake handles and sometimes have gears. These bikes will have steel or aluminum frames.

20″ Wheeled Bikes

When your child reaches the 5 to 9-year-old age range, their bikes have 20″ wheels and become more like adult bikes in their features and characteristics.

Gears, disc brakes, and suspension are common on 20″ wheeled bikes. This is the point when we start to see the different categories of bikes, such as road bikes and mountain bikes, allowing your child to choose a cycling discipline.

This is also the point where good bikes become expensive, so sizing and the type of bike are more critical.

24″ Wheeled Bikes

Your child will require a 24″ bike to transition to their first adult bike. These are suitable for kids aged 7 years old and over and have more features that are found on adult bikes.

Depending on the style of bike, 24″ wheeled bikes may have more gears, front and rear suspension, disc brakes, and more.

There are mountain bikes, road bikes, BMX bikes, and cruisers with 24″ wheels, so your child can pursue their favorite type of cycling.

The more features the bike has, and the more advanced they are, the more expensive it will be. Therefore, considering what your child actually needs from their bike is critical in the purchase decision.

A dad teaches his son to ride a bike on a tarmac path through a park.

Buying A Bike Based On Ability And Maturity

Now you know how to size a kids bike based on their measurements, but you should also consider your child’s ability and maturity. This is because everyone is different regarding confidence, physical ability, and enthusiasm.

The kids bike size chart is a great starting point, but your child may not be ready to move up to a more advanced bike in terms of its features. Your young rider may have the height to move to a bike with larger wheels but may not be ready to use the brakes or gears it is fitted with.

This is where your parental instinct kicks in, as you will understand how coordinated and mature your child is. You will also get a good indication when your kid goes for that first test ride on a new bike.

A kid drifts his orange mountain bike around a dirt track.

Now You Know How To Size A Kids Bike

To summarize, this method of how to size a kids bike using the kids bike size chart is the best way to get a starting point. But, you also need to consider your child’s ability level, their coordination, and their enthusiasm for riding a bike.

As a parent, you know your child better than anyone. With this information, you are in the perfect position to make the right decision.

Found this Article Helpful? Develop your cycling knowledge Further With The BikeTips Experts’ Guides Below!

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One of BikeTips' regular content creators, Tom lives in the French Alps. When he isn't writing, he can be found charging downhill on a mountain bike or snowboard. Tom's other passion is fitness, which goes a long way to help him make the most of the Alpine lifestyle.

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