Kid’s Bike Size Chart: What Size Bike Should I Get for My Child?

Kid’s Bike Size Chart: What Size Bike Should I Get for My Child?

“What size bike is best for my child?” is a question that many parents worry about. There are a lot of kid’s bikes out there and they all want your money, but what children’s bike sizes do you need? To help you out we’re going to break it down for you. Kid’s bike sizing is something that does not need to be feared, and getting the right bike can be a great bonding moment for you and your child. We want to help make it an easy process for you.

We’ll give you a kid’s bike size chart, tell you what to do if your child is between sizes, and we’ll even tell you the truth about training wheels. It is a scary moment the first time your child takes off on their bike, but we are here to help you make this process as safe as possible.

Simple Children’s Bike Size Chart – Age 3-11

Wheel Size

Child’s Age

Height of Child

Inside leg of Child

12” (Balance bike)

3 – 5

3’ 3” – 3’ 8”

30 – 40cm


4 – 6

3’ 5” – 3’ 10”

36 – 44cm


5 – 8

3’ 8” – 4’ 2”

40 – 54cm


7 – 9

3’ 10” – 4’ 6”

52 – 59cm


8 -11

4’ 2” – 4’ 9”

57 – 66cm

3 Tips That Will Help You Get the Right Size Bike for Your Kid

We are going to give you 3 really simple tips in order to get the correct bicycle sizes.

Use Our Kid’s Bike Size Chart

We are going to start with our simplest tip, which is our own kid’s bike size chart. The size guide will work well if there is not a manufacturer’s size guide available for the children’s bike you would like to buy. If there is a readily available manufacturers guide, take a look at it. We have put 16” and 18” kid’s bikes in the same column. The reason for this is that many manufacturers now only make a 16” or an 18” kid’s bike. You will see that it is mainly the 16” kid’s bikes that have stayed. Remember that kid’s bike sizes are always measured by wheel size and not frame size like adult bikes, and that is why an adult bike size chart will not work for children. Remember, 12” is the perfect toddler bicycle size so always get that as a balance bike. Now if you are unsure of your child’s inside leg size then please refer to our guide for measuring inside leg length in our “best bikes for 5-7 year olds” article. The chart is the same for girl’s bike sizes as it is for boy’s bike sizes; it is a universal kid’s bike sizes guide. 24” is generally considered to be the last of the youth bike sizes.

Do not Focus on an Age Range

If your child is tall or small for their age, buy a bike that is suitable for their size. Height is more important than age. You start by looking at age to get an idea of bike sizes for kids and then you move on to height.

Look for a Bike with Child-specific Geometry and Parts

It pretty much guarantees the bike will fit if you follow the manufacturer’s guidelines. These bikes will be more expensive, but your child will fit the bike in a much better way. You’ll find smaller brake levers, cranks, and bars that are the correct width. These parts will all make the bike much more comfortable for your child.

Should You Buy a Bicycle with Training Wheels or Not?

two kids riding on balance bikes

Training wheels very simply don’t train your child to ride. That is why we recommend to start your children off with a balance bike. Using a balance bike will also stop your child from using training wheels as a crutch. We have an article on balance bikes for toddlers that will give you all the pros and cons over using training wheels.

If your child did not feel like riding when they were a toddler, you can still turn your child’s bike into a balance bike. It is pretty simple to do so. If you buy online, keep in mind that pedals are never installed on shipped bikes. If you buy your bike from a shop, ask them not to fit the pedals. You now have an age and size-specific balance bike that can easily be converted to being a pedal bike.

What Should You Do if Your Child is Between Bike Sizes?

Children like to have growth spurts at awkward times, and this may not be helpful when buying them a bike. Most people want to buy a bike for Christmas or for a birthday; it will be an expensive purchase after all. You then have two choices if your child is between sizes on our children’s bicycle sizes guide and you are buying for one of these occasions.

The first one is to buy them a smaller bike. You know they will be growing out of it soon, but it is still the better of our two choices. On this bike, your child will have total control. They will be able to reach the bars and pull the brakes. On a bike like this, your child will enjoy riding.

Your other choice is to buy a bigger bike. You can then give your child the bike for the special occasion, but you will then have to put it away until they are big enough to ride it. This may not go over well.

The reason you do not want your child to ride a bike that is too big is that they will not be able to control the bike. You wouldn’t get in your car and push the driver’s seat back until you couldn’t reach the steering wheel and say everything is okay. It is needlessly dangerous.

Think about if your child goes to crash. How will your child get over and away from a bike that is too big? Chances are they will end up getting tangled up with the bike. Getting tangled will lead to more severe injuries. Don’t be the “it’s okay she will grow into it” parent.

How Long Until Your Kid Outgrows Their New Bike?

How long it will take a child to outgrow their bike is a question we are often asked in the bike trade. The correct answer is that none of us really know because everyone’s child is different. Some children might sprout one year and then forget to grow for another year. Always remember that the list of bike sizes for kids is based on averages, and they’re not necessarily catered to your child.

You can look at our kid’s bike size guide though and get an idea on how long a bike should last based on average child size. So if your child is 4, look at the chart and see what is the bike size for a 4 year old. You will see it is a 14”.

You could then reasonably expect their 14” bike to last them 2 years. If they are 6, the same 14” bike might last a month, or it might last a year, but if you buy them a 16” bike you can expect two years. If you look at the chart you will see that both 14” and 16” are a good bike size for a 6-year-old.

If you have a 5-year-old I would go with a 14”. The kid’s bicycle size chart says they can also fit on a 16”, and they can, but your child will prefer to ride the smaller bike.

The way I would break it down is I would buy a balance bike at 3 expecting it to last a year. Then at 4 I would buy a 14” bike and expect it to last 2 years. I would then be hopeful that each subsequent bike would also last 2 years.

How to Know When Your Child Has Outgrown Their Bike?

It should be easy to see when your child has outgrown their bike. It will look awkward when they are riding. It will look like their knees are coming up to meet their heads and their elbows will be sticking right out.

You want them to have a small bend at the elbow; this is their suspension and it gives them safe control. Their leg should almost be fully extended on the downstroke. If they are pushing their foot out sideways at the bottom of the pedal stroke, then the bike or saddle height is too small. If it’s the bike, you need a new one. If it’s the saddle, it’s a 2-minute fix.

Your child should also be able to tell you if they are on a bike that is too small. They will get sore thighs as they will have a limited range of pedaling motion. They will also become a lot more prone to bashing their knees off their bike stem. If your child is complaining about these issues, it may be time to size up.

If you are not quite sure whether or not your child is too big for their bike, measure the inseam of their leg then look to see where it fits on our children’s bike size chart. It will either tell you it is time for a new bike or it will put your mind at ease for a little while longer.