Bicycle Sizes For Kids: How To Buy And Measure Kids Bike Size

Bike riding is a healthy pastime and one of the best sports activities for your kid. It stimulates strength and promotes balance and overall fitness. But before your child embarks on a journey beyond your front lawn, they need a bike that suits their physical strength, size, and personal taste. So, in this article, we delve into the details of how to measure kids’ bike size and find them their first perfect bike. 

How To Measure Kid’s Bike Size And What To Look For

kid biking

1. Know What Wheel Size Your Child Needs

The first step in finding the perfect bike is to measure your child from the ground up. Their inseam (crotch to ground) will give you a good indication of how tall they are and how long the bike should be. Once you have their inseam measurement, you can use our Kids Bike Size Chart to find the right wheel size.

In general, if your child is under 10 years old, they’ll need a bike with 12-inch or 16-inch wheels. If they’re 10 years or older, they’ll need a bike with 20-inch wheels. However, wheel size is only one factor when choosing the right bike for your child. The other key factor is their inseam measurement.

2. Measure Their Inseam

To accurately measure your child’s inseam, first make sure they wear shoes that fit well. Then, using a yardstick or measuring tape, measure from their crotch to the ground.

When you have their inseam measurement, refer to our Kids Bike Size Chart to find the right size bike.

3. Consider Their Age, Height, And Weight

In addition to their inseam, you should consider your child’s age, height, and weight when choosing a bike. They may need a bigger bike if they’re on the taller or heavier side for their age.

4. Let Them Test Ride

Once you have a few bikes in mind, let your child test-ride them to see which one feels best. They should be able to sit on the seat with their feet on the ground and comfortably reach the handlebars. I

5. Get A Professional Fit

If you’re still unsure which children’s bike is right for your kid, take them to a local bike shop and have a professional fit them for a bike. They’ll be able to help you choose the right size and style of bike for your child.

Now that you know how to measure bike sizes for kids and what to look for, you’re ready to buy the perfect bike for your child. Just remember to have them test-ride it first to make sure they’re comfortable and confident on two wheels.


    Want the best cycling experience?
    Sign up for the latest bikes, gear, and accessories reviews out there.

    By signing up, you agree to our Privacy Policy
    and European users agree to the data transfer policy

    Kids Bike Size Chart

    Age Child’s Height Inseam Wheel Size Bike Type
    2–3 years old 2’10″–3’4″

    (85–100 cm)


    (35–42 cm)


    (30 cm)

    Balance Bikes
    3–4 years old 3’1″–3’7″

    (95–110 cm)


    (40–50 cm)


    (36 cm)

    Small Wheelers
    4–5 years old 3’7″–4’0″

    (110–120 cm)


    (45–55 cm)


    (41 cm)

    Middle Wheelers
    5–8 years old 4’0″–4’5″

    (120–135 cm)


    (55–63 cm)


    (51 cm)

    Road Bikes, Mountain Bikes, Cruisers, BMX Bikes
    8–11 years old 4’5″–4’9″

    (135–145 cm)


    (60–72 cm)


    (61 cm)

    Road Bikes, Mountain Bikes, Cruisers, BMX Bikes
    11+ years old 4’9″+

    (145+ cm)


    (70+ cm)


    (66 cm)

    Road Bikes, Mountain Bikes, Cruisers, BMX Bikes




    A balance bike is a perfect bike for 3 year old. They are ideal first bikes for toddlers and preschoolers (aged 2 to 4 years). They help riders develop a feel for balance and learn how to steer before they start pedaling. Most importantly, balance bikes allow kids to have fun while they learn how to ride.

    These children’s bikes usually come with 12-inch wheels. They are pedal-less and may or may not include a brake. Usually, the kids have to focus on using their feet and legs to move forward and stop. So, if you don’t want to get your kid a toddler car, gift them a balance bike, instead. 


    Small wheelers are a great option for kids who have outgrown their balance bike or first pedal bike. They are the first basic pedal bikes, which means they have all the features of bigger bikes, such as freewheel hubs and handbrakes. While they are bigger than balance bikes, you can still take a small-wheeler on a family road trip

    These bikes typically have 14-inch wheels and higher seat heights, making them more suitable for longer rides. Small wheelers usually have coaster brakes, but some models come with hand brakes. If possible, go for coaster brakes. These brakes need less manual dexterity and hand-eye coordination. 


    These bikes are designed for kids 4 to 6 years old or those between 110–120 cm tall. Like the 12-inch and 14-inch bikes, 16-inch bikes usually have coaster brakes. Some models, however, come with hand brakes. 

    Middle-wheelers are a great option for kids who have outgrown their small-wheeler bike or are ready for their first “big kid” bike. These bikes typically have 20-inch wheels and higher seat heights, making them more suitable for longer rides. Middle wheelers also have a gear set, freewheel hub, and steel/aluminum frames. Some scooters for kids also fall under this category.

    These bikes allow your kid to pick up real speed. Therefore, your child must have the necessary hand-eye coordination skills and dexterity for balance. 

    Note: If you want to know the ideal bike size for a 7-year-old, consider the following bikes. 


    These bikes are designed for kids 5 to 9 years old or those between 120–135 cm tall. These bikes will have gear sets, hand brakes, suspension systems, and more. Bike manufacturers in this category often use terms like “road bike,” “mountain bike,” or “cruisier” to attract customers. This means this is the level where specialization begins. So, expect a variety of styles and features. 

    Therefore, consider the type of riding your kid will be undertaking: off-road, racing, on-road, jumping, etc. Remember, a good bike won’t come cheap. If you’re not careful with your choice, you may end up with a model that may not be suitable for their needs. 


    BMX is the best kids bikes. They are perfect for kids who love to ride hard and fast. They’re built tough to handle all the bumps and jumps of BMX riding. Initially, they were designed for dirt racing on jumpy tracks. However, they have a much broader appeal today.

    Most BMX bikes have 20-inch wheels, but some models have 24-inch or 26-inch wheels. They are built tough and for hard rides. Moreover, these bikes usually have only one gear and feature a lightweight frame and knobby tires. 

    BMX bikes include Cantilever, VB-rakes, U-Brakes, Gyro, Coaster, Caliper, or Mechanical Disc Brakes.


    Think of these bikes as more of transition-to-adult bikes. This is because they come with adult bike features such as front suspensions, up to 36 gears, etc. Some of them even come with advanced features like hub brakes. However, these extra features mean higher prices and more chances of going wrong. 

    BMX bikes, cruiser bikes, mountain bikes, and road bikes – are all available in the 24-inch wheel category. Usually, our advice for picking a bike in the category is to go for simple options. 

    What To Do When Your Child Is In Between Sizes Or Has Outgrown Their Bike 

    practicing on bike

    If your child is in-between sizes or has outgrown their bike, don’t worry! Here are a few things you can do:

    – Look for a bike with an adjustable seat and handlebar height. This will give your child some extra room to grow.

    – Get a bike with bigger wheels. For example, if your child is between sizes for a 16-inch bike and an 18-inch bike, get the 18-inch bike. The bigger wheels will make it easier for your child to ride.

    – Get a bike with coaster brakes. Coaster brakes are easier to use than hand brakes, so they’re a great option for kids who are still learning how to ride.

    With a little research, you can find the perfect bike for your child.

    Where To Buy Kids’ Bikes?

    bike shop

    Below are a few places you can buy kids’ bikes:

    Local Bike Shops

    Bike shops typically have a good selection of kids’ bikes. They can also help you find the right size and make sure the bike is properly tuned.

    Online Retailers

    There are many online retailers that sell kids’ bikes. You can often find good deals on bikes from online retailers. Just ensure you complete your research before buying to make sure you’re getting a quality bike.

    Department Stores

    You can sometimes find kids’ bikes at department stores. However, it’s important to note that not all department stores sell quality bikes. We suggest sticking with reputable brands that you know and trust.

    No matter where you buy your child’s bike, make sure you get a bike that’s the right size and properly tuned. With a little bit of care, your child will be cruising on two wheels in no time!

    Key Takeaways

    So, we hope now you know how to determine the size of a child’s bike. Here are the three things to remember:

    1 – Use your child’s height and inseam to find the right size bike.

    2 – If your child is between sizes, opt for a bike with bigger wheels or adjustable seat and handlebar height.

    3 – When in doubt, always err on the side of caution and get a bigger bike. Your child can always grow into it, but they can’t ride a bike that’s too small.

    Good luck!

    About the author
    Bicycle Sizes For Kids: How To Buy And Measure Kids Bike Size — Bike Hacks