Figuring out What Size Bike Fits Best for a Kid

Published by 
Jess Miller
Last updated: 
November 22, 2019
Boy riding bicycle

So much about childhood has changed in the world between your childhood and your son or daughter's childhood. It's refreshing to see the few hobbies from your childhood that are still around today, like bicycling. That's why if you're trying to figure out what size bike fits best for a kid, it's a happy problem to have.

It's still a problem, though. Choosing wrong when you're deciding what size bike for a kid experience, can put your child at risk.

In fact, accurate sizing is one of the top cycling safety suggestions from the National Highway Traffic Safety Administration. Finding the right size now can save your family from stress and improve safety.

Understanding Bike Sizes for Kids

JOYSTAR Kids Bike with Training Wheels for Girls & Boys, 12 14 16 Inch

First things first: You need to know how manufacturers label kid's bike sizes.

When adult bikes list their size, that number is the frame size. On kid's bikes, the number you'll see is the wheel size. Specifically, it's the diameter of the wheels.

Kid's bike sizes range from 12-inch bikes to 24-inch bikes. If your child is too big for a 24-inch bike, they're ready for adult bike sizes.

Keep in mind that this measurement only applies to the wheel sizes. The sizes for the frames and the way they're built can vary from one manufacturer to another. This is why it's always best to have your child try a few bikes and see which one fits the best.

Can I Know What Size Bike Fits Best for a Kid by Knowing Their Age?

Toddler Riding Bicycle on Road
Image source: pexels

Not reliably. Kids in the same age group can vary widely in their sizes, so it's impossible to know what size bike fits best for a kid based on their age alone.

This is even true if your child is the exact average in height and weight for their age. Not all manufacturers know what that average is, so it's not a reliable measure, even for the best kid's bikes.

The age on a bike could help you know where to start, but there are other ways to figure out your child's bike size more accurately.

How to Figure out What Size Bike Fits Best for a Kid

As you shop for your child's bike, there are a few different measurements you can use to get a more predictable idea of which bikes will work best.

Sizing based on your child's height

One of the first things you should do to find the right size of bike for your child is to measure their height.

Make sure you measure your child's height soon before you start bike shopping. Every parent has witnessed how quickly kids can grow, so if you rely on the height your pediatrician recorded a year ago, it's probably wrong.

If your child is 3 feet 4 inches tall or less, they're best suited for a 12-inch bike. For a child between 3 feet and 3 feet 7 inches, a 14-inch bike will work best. A 16-inch bike will be the best fit for a child between 3 feet 6 inches and 4 feet tall.

The next standard size is a 20-inch bike, which tends to work well for kids between 3 feet 11 inches and 4 feet 6 inches tall.

Huffy Kids Bikes 16 & 20 inch with Streamers and BMX Pegs

Finally, if your child is between 4 feet 4 inches and 4 feet 9 inches tall, they're better suited for a 24-inch bike. Any child more than 4 feet 9 inches tall is ready for an adult-sized bike.

There are plenty of size charts out there, and some bike manufacturers have their own, so check theirs first. Regardless, you'll notice that there is some overlap. This because there are other factors that affect how a bike will fit your child, which is why height shouldn't be your only deciding factor.

Sizing based on your child's inseam

The other important measurement you'll need to know to figure out the right size bike for a kid like yours is your child's inseam.

When you measure the inseam, you'll measure from your child's crotch to the floor. It's best to do this while your child is wearing the same shoes they'd wear while riding their bike.

In general, you want your child's inseam to be within 2 to 5 inches of the wheel's diameter.

For instance, let's say your child has an 18-inch inseam. This means they could fit a 14-inch, 16-inch, or 20-inch bike. You can use their height to see what size bike fits best for a kid -- your kid.

Checking the bike's measurements

Another handy way to find the right bike for your child is to see if the bike's manufacturer has listed its measurements.

The most important measurement you want to look for is the standover height. This is the height from the ground to the bar below the bike seat when the bike is standing up straight.

If a bike lists its standover height, compare it to your child's inseam. You want a standover height that is a few inches shorter than the child's inseam.

Trying Before You Buy

Kids Bicycle
Image source: pixabay

For that reason, it's always best to have your child try a bike before you buy it. At the bare minimum, they should sit on the seat and stabilize their body on the bike. Specialized bike shops may have an area where your child can ride the bike back and forth to give it a try.

Of course, there are times when you're buying the bike as a surprise for your child. In this case, use the measurements above to take your best guess. When you buy the bike, let the shop know the situation and ask what their return policy is.

What Size Bike Fits Best for a Kid like Yours?


Gif source: giphy

Buying your child a bike can be a thrill for any parent, especially if it's their first bike. You're relishing in the opportunity to share something from your own childhood with them and bring them into your world.

Whether this is your child's first bike or their fifth bike, making the right choice in bike size can make all the difference. It gives them a way to be more active and have fun while also helping them stay safe as they enjoy it.

The tips above can be a starting point for narrowing your bike selection and finding the perfect one for your child.

Which methods have you used in the past to find the right size bike for a kid? Let us know your favorites in the comments.

Featured image source: pexels

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