Kids Bike Size Chart (FULL Size Guide)

One of the first big toys that children get when growing up is a bicycle. This is often a balance bike, or a small cruiser bike with training wheels, which helps kids to prepare for riding a bigger bike as they grow older. The ultimate kid’s bike size chart will help you determine which bike your kid needs for their size and age.

To help you buy the perfect bike for your kid, we will be looking into the different frames and bike sizes. This will give you a solid idea of what your kid will need and the specific bike that will likely work for them. We will break down how you should go about selecting the right bike for your kid and understanding the things to consider when answering the question “What bike should I buy for my kid?”

Kids Bike Size Chart

Understanding The Kids Bike Size Guide: Finding The Right Size Bike

It is important to understand some of the fundamentals that drive a kid’s bike size. Here are a few of the fundamental things to keep in mind:

1. Understanding The Right Wheel Size

Remember that these are general guidelines, and it’s crucial to ensure the bike fits the child properly. Have the child test the bike, making sure they can touch the ground with their tiptoes when seated and that they can easily reach the handlebars and brakes.

When choosing a wheel size for a children’s bike, it’s essential to consider the child’s age, height, and skill level. Here is a general guideline for children’s bike wheel sizes based on age and height:

  1. 12-inch wheels: Suitable for children aged 2 to 4 years old or with a height of 85 cm to 100 cm (33-39 inches). These bikes typically come with training wheels to help children learn to balance and ride.
  2. 14-inch wheels: Suitable for children aged 3 to 5 years old or with a height of 90 cm to 105 cm (35-41 inches). Like 12-inch bikes, these often include training wheels for beginners.
  3. 16-inch wheels: Suitable for children aged 4 to 6 years old or with a height of 100 cm to 115 cm (39-45 inches). Training wheels are common for this size as well, but some kids might be ready for a bike without them.
  4. 18-inch wheels: Suitable for children aged 5 to 8 years old or with a height of 105 cm to 125 cm (41-49 inches). These bikes cater to children who have mastered balancing and are transitioning to a larger bike.
  5. 20-inch wheels: Suitable for children aged 6 to 9 years old or with a height of 115 cm to 135 cm (45-53 inches). At this size, bikes start to resemble adult bikes and may include gears.
  6. 24-inch wheels: Suitable for children aged 8 to 12 years old or with a height of 130 cm to 145 cm (51-57 inches). These bikes typically have multiple gears and are designed for more experienced young riders.

2. Using Estimates – Nothing Beats Just Trying it Out

Ideally, you would want try the bike out and have your kid sit on it and try it out. However, that makes a big reveal during a birthday or holiday a little hard. If this is a standard purchase just head to a big box store and have the kid try it out, or order from Amazon as close as possible and then return it as necessary.

When trying out the bike isn’t an option, you have to rely on estimates based on your kid’s age, height, and some other measurements. However, you should always do some research on the bike manufacturer to find out whether or not the bike you have selected would be functional and useful.

3. How And What Should You Measure When Determining Size?

You want to start by measuring the inseam and the height of your kid. Once you have these measurements.

When choosing a bike, it’s crucial to have the child test ride it, ensuring they can comfortably reach the handlebars and brakes and that the bike’s size allows them to maintain proper control. Safety and comfort should be the top priorities.

When determining the right size for a kid’s bike, it’s essential to consider both the child’s measurements and the bike’s dimensions. Here are the key factors you should measure:

  1. Child’s inseam: Have the child stand against a wall, wearing the shoes they’ll use when cycling. Place a book between their legs, with the spine firmly against their crotch (simulating the bike seat). Measure the distance from the floor to the top of the book spine. This measurement will help you select a bike with the right seat height for the child.
  2. Child’s height: Measure the child’s overall height. This will give you a general idea of the appropriate bike size based on the child’s age and height guidelines provided in the previous response.
  3. Child’s reach: Have the child extend their arms out in front of them, then measure the distance from the tip of one middle finger to the other. This measurement, known as “wingspan,” can help you determine if the child can comfortably reach the handlebars and brakes on a specific bike.

4. Check The Bike Specs

Once you are done with the kid’s measurements (and have written them down!) you will need to use them with the bike specs.

If you check any online retailer, you should see a bike size guide to looking at when you choose a bike. This is where you would want to compare them to your kid’s measurements to determine the right bike. There are a few key bike measurements to understand:

  • Bike seat height: Check the bike’s minimum and maximum seat height, ensuring that it can be adjusted to fit the child’s inseam measurement. The child should be able to touch the ground with their tiptoes when seated on the bike.
  • Bike frame size: While frame size is less critical for children’s bikes, it’s essential to ensure that the bike isn’t too large or small. Most kids’ bikes are measured by wheel size rather than frame size, so refer to the guidelines provided in the previous response.
  • Bike wheelbase: The wheelbase is the distance between the centers of the front and rear wheels. A longer wheelbase provides more stability but may be harder for a child to maneuver. Make sure the wheelbase is appropriate for the child’s skill level and intended use.

Other things to consider about the bike:

Frame Design: The way the frame is designed varies from bike manufacturer to bike manufacturer. Some might have a bulge in the frame, which could make it slightly higher. You should also consider the overall size and the design specs of the frame.

Training Wheels: This one might be a bit off-topic, but having good trainer wheels can make a big difference. However, they should be comfortable and should not lift the bike too much. The Geminiman Bicycle Training Wheels are some of the best that you can find on the market today.

Kids on bike with Trainer Wheels
Kid riding a bike with training wheels

Accurate Kids Bike Size Chart For Buying A Bike For Your Child

Now that you have a better understanding and a way of calculating the right size for your kids’ bike, you should also look at how the most common charts are set up. The most common bike charts would be similar for most bike brands. Here is what you can expect when it comes to a traditional bike size chart from an online retailer.

Bike Size (Wheels)Recommended AgeHeight (Inches)Inseam (CM)
12-inches2 – 433″ – 39″35-42 cm
14-inches3 – 535″ – 41″40-50 cm
16-inches4 – 639″ – 45″45-55 cm
18-inches5 – 841″ – 49″50-60 cm
20-inches6 – 945″ – 53″55-63 cm
24-inches8 – 1251″ – 57″60-72 cm

This is a basic chart for buying a kids’ bike. You might find that it varies depending on the bike you choose and the brand. This chart should help you figure out what size bike to buy to limit how many new bikes you need to buy as your kid grows.

We recommend using these sizes to ensure that you have the ultimate bike for your kid to use and ensure you have the ideal bike for your kid at their age and height.

Key Features To Look For When Finding The Right Size Bike For Your Kid

Aside from looking at all the features that make up the size of the kids’ bike, you should also consider looking at additional things like special features. You should use the chart with the below special features to make sure that the bike your kid chooses is functional:

Bike Type

When choosing a bike for a child, consider their age, height, skill level, and intended use. It’s essential to ensure the bike fits the child properly and provides a comfortable and safe riding experience.

There are several types of bikes designed specifically for kids, catering to different age groups, skill levels, and riding purposes. Here are some common types of kids’ bikes:

  1. Balance bikes: Designed for young children (around 18 months to 5 years old), balance bikes have no pedals, chains, or gears. They help kids develop balance and coordination skills by learning to push the bike with their feet and glide along. These bikes are an excellent introduction to cycling before transitioning to a pedal bike.
  2. Pedal bikes: Pedal bikes are the standard type of bike with pedals, chains, and gears. They come in various wheel sizes, such as 12-inch, 14-inch, 16-inch, 18-inch, 20-inch, and 24-inch, to accommodate children of different ages and heights. Many pedal bikes for younger kids include training wheels to help them learn to balance.
  3. BMX bikes: BMX (bicycle motocross) bikes are designed for off-road racing, stunt riding, and freestyle. These bikes typically have 20-inch wheels, a compact frame, and single-speed gearing. They are suitable for kids who are more experienced riders and are interested in performing tricks or participating in BMX competitions.
  4. Mountain bikes: Mountain bikes are designed for off-road cycling and come with features like wider tires, sturdy frames, and suspension systems. Kids’ mountain bikes typically have 20-inch or 24-inch wheels and are suitable for children who enjoy riding on dirt trails or rough terrain. These bikes may also have multiple gears for tackling hills and various terrain.
  5. Road bikes: Road bikes are designed for speed and efficiency on paved surfaces. Kids’ road bikes are generally lightweight, have narrow tires, and drop handlebars. They may have multiple gears to help riders maintain speed and tackle hills. These bikes are suitable for kids who are experienced cyclists and want to participate in road cycling or racing events.
  6. Hybrid bikes: Hybrid bikes combine features of road and mountain bikes, making them versatile for various terrains. They typically have a more upright riding position and wider tires than road bikes but are lighter than mountain bikes. Kids’ hybrid bikes usually come with 20-inch or 24-inch wheels and are suitable for children who want a bike for casual rides, commuting, or recreational cycling on various surfaces.


These brands are just a few of the many options available for kids’ bikes. When choosing a bike for your child, prioritize fit, comfort, and safety, and consider their age, height, and intended use.

There are many kids’ bike brands that offer quality bicycles designed specifically for children. Here’s a list of some popular kids’ bike brands, along with a brief description of each:

  1. Strider: Strider is known for its balance bikes, designed for children as young as 18 months. They focus on helping kids develop balance and coordination skills, providing a smooth transition to pedal bikes.
  2. WOOM: WOOM specializes in lightweight, high-quality kids’ bikes, ranging from balance bikes to 24-inch pedal bikes. They prioritize proper fit and ergonomics, ensuring a comfortable riding experience for children.
  3. Guardian: Guardian Bikes offers kids’ bikes with a focus on safety. They feature the patented SureStop braking system, which prevents head-over-handlebar accidents and makes it easier for children to stop their bikes effectively.
  4. Frog: Frog Bikes is a British brand that produces lightweight, versatile bikes for children. They offer a range of bikes, including balance bikes, first pedal bikes, hybrid bikes, road bikes, and mountain bikes, catering to various ages and skill levels.
  5. Islabikes: Islabikes is a UK-based brand that creates lightweight, high-quality bikes specifically designed for children. Their bikes cater to different ages and abilities, from balance bikes to road, mountain, and hybrid bikes.
  6. Specialized: Specialized is a well-known brand in the cycling industry that also offers a line of kids’ bikes. They produce balance bikes, mountain bikes, and road bikes for children, with a focus on quality and performance.
  7. Trek: Trek is another established brand in the cycling world that offers a range of kids’ bikes. Their lineup includes balance bikes, mountain bikes, road bikes, and hybrid bikes, designed to cater to various ages, heights, and skill levels.
  8. Giant: Giant is a leading bicycle manufacturer that also produces a line of kids’ bikes. They offer balance bikes, BMX bikes, mountain bikes, and road bikes, ensuring options for children with different riding interests and skill levels.
  9. Raleigh: Raleigh is a long-standing bicycle brand that offers a range of kids’ bikes, including balance bikes, mountain bikes, road bikes, and hybrid bikes. Their bikes are designed for various ages and skill levels, emphasizing durability and quality.


While the carbon fiber bike is by far one of the best bikes that you can buy, it is not worth it to go to such lengths for a kids’ pedal bike. And if you think it is, then please adopt me (a grown man) and buy me a new frame.

Kids bike frames can be made from a variety of materials, including:

  1. Steel: This is a common material used for kids’ bike frames due to its strength, durability, and affordability. Steel frames are often found on entry-level bikes.
  2. Aluminum: This material is lighter than steel and is often used on higher-end kids’ bikes. It is also resistant to rust and corrosion.
  3. Wood: Although not as common as other materials, some kids’ bikes are made from wood. These bikes are usually handmade and can be both lightweight and durable.
  4. Titanium: (Expensive!) Another lightweight and strong material, titanium is less common on kids’ bikes due to its high cost.
  5. Carbon fiber: (Expensive!) While less common on kids’ bikes due to its high cost, carbon fiber frames are lightweight and strong. They are often found on high-end road bikes and mountain bikes.

The choice of material for a kids’ bike frame will depend on factors such as the child’s age, weight, and riding ability, as well as the intended use of the bike.

Bike Fit

Finally, the perfect bike fit is one of the most important aspects to consider and each bike would look and work differently. If there is one thing that you can take from all the advice we have given you and you have access to the bike, you should consider the following. You want your kid to stand over the frame of the bike with feet flat on the ground.

The easiest way to make sure that your bike will fit is to get close to the bike and have a physical feel for the bike. It might take some time for you to get used to the bike, but it should work as a treat for most people to ensure value.

kids bike on the road

How Do Adult Bike Sizes Differ From Kids’ Bike Sizes?

Overall, the main difference between adult and kids’ bikes is the size and scale of the bike components, which are designed to accommodate the different body sizes and riding needs of adult and child riders.

For the most part, bike manufacturers try to make sure that they can have the sizes synch up with one another and have them be similar to the adult sizes to avoid confusion.

Adult bike sizes differ from kids’ bike sizes in a few key ways:

  1. Frame Size: Adult bikes typically have larger frames than kids’ bikes, to accommodate the larger body size and longer legs of an adult rider. Adult bikes come in a wide range of frame sizes, which are measured from the center of the bottom bracket to the top of the seat tube.
  2. Wheel Size: Adult bikes typically have larger wheels than kids’ bikes. Most adult bikes have 26-inch, 27.5-inch, or 29-inch wheels, while kids’ bikes typically have 12-inch, 16-inch, 20-inch, or 24-inch wheels.
  3. Handlebars and Controls: Adult bikes usually have wider handlebars and more advanced brake and gear controls than kids’ bikes. This is because adult riders need more control and stability while riding at higher speeds and on more challenging terrain.
  4. Weight Capacity: Adult bikes are designed to support the weight of a full-grown adult, whereas kids’ bikes have lower weight capacities.

Understanding BMX Bike Sizes

It’s important to note that these are general guidelines and that the size of BMX bike that’s right for a rider may also depend on their riding ability, riding style, and personal preference. It’s always a good idea to consult with a bike shop or a knowledgeable salesperson to ensure that you’re getting the right size bike for your needs.

Micro MiniUnder 53’6”-4’0”
Expert XL10-135’3”-5’7”

BMX bikes come in a variety of sizes to accommodate riders of different ages and heights. Here is a general guide to BMX bike sizes by age and height:

  1. 12-inch BMX bikes: These bikes are suitable for kids between the ages of 3 and 5, who are between 2’10” and 3’6″ tall.
  2. 16-inch BMX bikes: These bikes are suitable for kids between the ages of 5 and 7, who are between 3’6″ and 4’0″ tall.
  3. 18-inch BMX bikes: These bikes are suitable for kids between the ages of 6 and 9, who are between 4’0″ and 4’6″ tall.
  4. 20-inch BMX bikes: These bikes are the most common size for BMX bikes and are suitable for riders of all ages and heights. They are typically used by riders between 4’6″ and 5’10” tall.
  5. 24-inch BMX bikes: These bikes are less common and are designed for riders who are taller than 5’10”.

Kids Bike Sizing Summary

When choosing the ideal bike for your kid, you should always look at the child’s size, the bike specs, and any important features. I would love to see some of your comments when it comes to the ultimate kids’ bikes on the market today.

About Martin

I am Martin, I am the author of this blog. My main interests include cycling. That's why this blog was created. I have always been interested in technology and how bicycles are made, so I built one myself.

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