How to Measure a Kids Bike

  • By: Kevinsmak
  • Date: July 20, 2022
  • Time to read: 11 min.
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To measure a kid’s bike, consider factors like:

  • The type of the bike
  • The age of the kid
  • Height of the child
  • The inseam
  • Their ability and maturity
  • The experience they have had with bike

You can also look at the bike’s tire size to help you make a decision on the right bike. 

It can be difficult to find the right bike for your child. With all of the different sizes and brands available, it can be hard to know where to start.

In this blog post, we will discuss how to measure a kid’s bicycle so that you can find the perfect one for your child. We will go over the different measurements you need to take, as well as some tips on how to choose the right size bike for your child.

What to Consider When Measuring a Kids Bike

With a lot of brands producing bikes in different sizes, it can be confusing to know which one is right for your child.

Before we go deeper and discuss the nitty-gritty of measuring a bike, let’s take a step back and see what other factors you should consider when purchasing a kid’s bike:

The type of bike

The type of bike you want to buy will also play a role in what size you need to get. For example, a mountain bike will require a different size than a road bike.

Your child’s age

Age is an important factor to consider when purchasing a kid’s bicycle. This is because as children grow, they will need a bigger bike.

It’s important to choose a bike that your child will be able to grow into, rather than one that they will quickly outgrow.

Your child’s height

Height is another important factor to consider when measuring a kids bike. You will want to make sure that your child can comfortably reach the handlebars and pedals.

If they can’t, then the bike is too big.

Your child’s inseam

Inseam is the distance from your child’s crotch to the ground. This measurement will help you determine the size of the bike frame.

You will want to make sure that your child can comfortably straddle the bike with their feet flat on the ground. If they can’t, then the bike is too big.

The child’s riding experience

You will also want to consider your child’s riding experience when choosing a bike. If they are just starting out, you will want to get a smaller bike that is easier to control.

As they get more experienced, you can move up to a bigger bike.

Kid’s maturity

Not all kids are the same, even if they are the same age and height. Some kids are more mature than others and may be able to handle a bigger bike.

If you’re not sure, it’s always best to err on the side of caution and get a smaller bike. Now that we know the general things to consider, let’s get into how to measure a kids bike.

How to Measure a Kids Bike

Here we will dive deeper and look at how to measure a kid’s bike by the factors we have listed above. We will give you as much detail as possible so that you can make an informed decision when purchasing a bike for your child. Here we go:

How to measure your kid’s bike by:

1. The Type of Bike

There are several types of bikes for kids, and each type is suitable for a certain age of the child. They include the following:

Balance bikes (Age 2-4 years)

A balance bike is basically a bike that doesn’t have pedals. This is a great type of bike for kids who are just starting to learn how to ride.

They are small and lightweight, which makes them easy to control.

A balance bike may come with brakes but most don’t. If you’re considering a balance bike for your child, make sure to get one with brakes so that they can stop the bike if they need to.

But since the kid is still young and you will probably be watching them most of the time, brakes may not be a necessity.

Small wheelers (Age 3-5 years)

A small wheeler is a bike with small wheels, usually 12-14 inches or smaller. This type of bike is great for kids who have outgrown their balance bike but aren’t ready for a bigger bike yet.

Small wheelers are lightweight and easy to control, which makes them perfect for kids who are still learning to ride.

They often come with a few features found on bigger bikes. They have pedals, coaster brakes, and sometimes even hand brakes. But since they have small wheels, they are not suitable for off-road riding.

Since they are transition bikes, you want to keep things as simple as possible. Avoid getting a bike with too many features that your child won’t be able to use yet.

Middle wheelers (Age 4-6 years)

Now we’re getting into the bigger bikes. Middle wheelers are bikes with 16-20 inch wheels.

This is the type of bike that most kids will need when they outgrow their small wheeler.

Middle wheelers are still lightweight and easy to control, but they can go faster and handle more rugged terrain than a small wheeler. They often come with handbrakes and freewheel hubs so that kids can coast without pedaling.

Some middle wheelers come with a gear set, but this is not always necessary as kids this age usually don’t need the extra speed. But if your child is a bit more adventurous, then getting a bike with gears may be a good idea.

Since these bikes can really pick up speed, it is important that you make sure your kid can handle the bike before you let them loose.

Big wheelers (Age 5-9 years)

I am calling these categories big wheelers because I have actually seen a few adults ride these types of bikes. Big wheelers have 20-24 inch wheels and they are basically miniaturized adult bikes.

If your child is on the taller side or is quite adventurous, then this may be the type of bike they need. They can handle more rugged terrain and go faster than the smaller bikes.

And since they are so close in size to an adult bike, they can easily transition to a bigger bike when they’re ready.

Most big wheelers come with handbrakes and gears. And some even come with suspension, which is great for off-road riding. Just make sure that your child is able to handle the bike before you let them loose.


I just had to mention this type of bike because it is so popular with kids. BMX bikes are designed for racing and tricks, and they usually have 20-24 inch wheels.

They are heavier than the other bikes on this list but they are also very durable. And if your child is into racing or doing tricks, then a BMX bike is definitely the way to go.

Just make sure that your child is tall enough to handle the bike. And if they are into tricks, then getting a bike with handbrakes is a good idea.

2. The Kid’s Age

Here we will look at the wheel size and the age for which it is recommended.

2-3 years

The appropriate wheel size here is 12 inches or 30cm. Since the kid is still young, you want to get a bike that is lightweight and easy to control.

A 12-inch bike is perfect for kids who are still on the balance bike.

3-4 years

Get them a 14-inch bike with a few features of the bigger bikes. The bike should still be lightweight with coaster brakes.

Pedals may also be included but they are not necessary.

As the kid starts to grow, you may want to consider getting a bike with hand brakes. You also want to make sure that the bike comes with a kickstand so that your child can park their bike without tipping it over.

4-5 years

A 16-inch or 41-cm bike is perfect for kids in this age group. The bike should be lightweight with coaster brakes and hand brakes.

Gears are not necessary but they may be included on some bikes.

You also want to make sure that the bike has a kickstand so that your child can park their bike without tipping it over. You can start introducing them to bikes with more features so they get used to them as they outgrow their smaller bike.

5-8 years

Get this kid a 20-inch or 51-cm bike. If they still like biking at this age, they should already be conversant with most features of a bike.

The bike, however, should still be lightweight especially if your kid is smaller in size. You don’t want them to be bogged down by a heavy bike.

The bike should come with almost all the features a bigger bike has. From handbrakes to gears and even a suspension system. However, if your kid isn’t into biking that much, then you can save some money by getting them a bike without all the bells and whistles.

8-11 years

A 24-inch or 61-cm bike is perfect for kids in this age group. This is the time when they are ready to transition into a bigger bike.

The bike should come with all the features of a bigger bike including handbrakes, gears, and even a suspension system.

This is also the age when you want to start looking at mountain bikes or BMX bikes if your child is into racing or tricks. Just make sure that the bike is lightweight and easy to control.

11+ years

Anything above and including a 24-inch or 61-cm bike is perfect for kids in this age group. This is the time when they are ready to transition into a bigger bike.

3. The Kid’s Height

This is among the most important factors to consider when getting a bike for your kid. You don’t want them to be too cramped up or too stretched out on the bike.

Here is a general guide on how to choose the right sized bike based on your child’s height.

  • 36″-39″: 12-inch bike
  • 37″-44″: 14-inch bike
  • 41″-48″: 16-inch
  • 45″-54″: 20-inch
  • 49″-59″: 24-inch
  • 56″+: 26-inch

Most parents often choose to go with the height when measuring their kids’ bikes. But perhaps you are wondering:

What is the best way to measure my kid’s height for a bike? Here’s how:

  • Have the kid stand straight against, say, a wall.
  • Use a tape measure to measure from the ground to the top of their head.
  • Record this measurement in both inches and centimeters.
  • You can use a meter rule if you don’t have a tape measure. Just make sure that you record and convert the measurement to inches as most bike sizes are based on inches.
  • Use a bike size, most of which you can find online, to determine the appropriate bike size for your kid.
  • You can also use this guide to get an idea of what size bike your kid needs:

4. Your Child’s Inseam

The inseam is the distance from the crotch to the ground. To measure it, you will need a hardcover book and a tape measure. Here’s how to go about it:

  • With their shoes on, let your kid stand straight against a wall. Their feet should be slightly apart.
  • Place the book in between their legs at the crotch and have them hold it in place.
  • Use a tape measure to measure from the top of the book (the part that’s directly against their crotch) to the ground.
  • Record this measurement both in inches and centimeters. That’s the inseam.

So now you know how to measure your kid’s inseam. But how do you use that to get them the right bike size? Here we go:

  • 14″-17″: 12-inch bike
  • 16″-20″: 14-inch bike
  • 18″-22″: 16-inch
  • 22″-25″: 20-inch
  • 24″-28″: 24-inch
  • 26″+: 26-inch bike

When measuring the inseam, you want to be careful not to pull the measuring tape too tight. Just let it rest lightly against their skin.

Also, make sure that you measure the inseam from their crotch and not their waist.

Another thing to keep in mind is that kids grow quickly. So, even if you measure their inseam and they seem to fit perfectly into a certain bike size, it’s best to go with the next size up.

This way, they will have room to grow into the bike.

5. The Kid’s Ability and Maturity

For various biological factors, kids grow differently and they have varying abilities when it comes to playing with moving objects like bikes. So, even if your kid is the same age and height as another kid, they might not be able to ride a bike of the same size.

Some kids are just ready to ride a bigger bike earlier than others. When choosing a bike size for your kid, you also want to consider their ability and maturity.

If they seem to be able to handle a bigger bike, then go for it.

On the other hand, if you think they might be better off with a smaller bike, then go for that instead. Just because they are the same age or height as another kid doesn’t mean they should ride the same size bike.

But how do you know your kid is mature enough to handle a bigger bike? Here are some tips:

  • They have lost interest in the bike they are currently riding and they seem to be ready for a change.
  • They have outgrown their current bike in terms of size and ability.
  • You can see them handle the current bike they are on better than you thought. For instance, if they are on a small wheeler that came with a brake, you may see them using the brakes well without any accidents. Or, they could start braking with their feet if the bike doesn’t have a handbrake.
  • You’ve seen them handle other moving objects well like scooters or skateboards. If they can control those, they can probably control a bike too.

In the end, only you know your kid best and whether they are ready for a bigger bike. Just use your best judgment and don’t be afraid to go for the next size up if you think they are ready for it.

6. The Kid’s Experience

This is among the most obvious factors that will affect what size bike your kid needs. If they are new to biking, then they will obviously need a smaller and simpler bike to start off with.

As they gain more experience, they will be able to handle a bigger and more complex bike. So, if your kid is just starting out, don’t get them a big mountain bike thinking they will grow into it.

They won’t be able to ride it and they will probably get discouraged.

A good rule of thumb is to start them off with a bike that has 12-inch wheels. Once they have outgrown that, you can move up to a 14 or 16-inch bike.

However, other factors such as age and height still matter. You don’t want to buy an 11-year-old a bike that would best suit a 7-year-old even if they have ridden one before.

The best thing to do here is to look for an age-appropriate bike but with simpler features. Once they have gotten the hang of biking, you can then move them up to a bigger and better bike.

When in doubt, always go for the smaller size. It’s better for them to ride a small bike that they can handle than a big bike that they can’t. You can always buy them a bigger bike when they’re ready for it.


Now that you know how to measure a kid’s bike, you’re well on your way to choosing the perfect bike for them.

Just remember to keep all the factors discussed in this article in mind and you’ll be sure to find the right bike for your kid.

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