Kids bike size guide with chart: 3 Fast and easy sections to know it all

Cycling is a great way for kids to have fun, get healthy and learn new skills. We want to make sure your kid has the perfect sized bike so their experience is safe and enjoyable.

kids bike size guide

Kids’ bike size charts are just the tip of the iceberg, that should be used only as a road map with several roads, but only one path for choosing the perfect sized bike for your kid.

This kid’s bike size guide will serve you as a local guide giving you the right turns and best shortcuts to get you on the right path of doing so. 

27 years ago I had my first bike and since then, bikes have been my perfect companions that lead me to awesome adventures and to meet great friends.

Biking should be a joyful, safe and comfortable experience for all riders but most importantly for kids and this can only be achieved 100% with a well-fitted bike. 

The experience for a kid with a bad-sized bike will be an unpleasant one and sometimes a dangerous one with the most likely outcome of the kid abandoning cycling completely.  

I know how important it is for kids to feel safe and at the same time experience the freedom that comes with bikes. I also know that for parents choosing the right bike can be a big quest with lots of doubts.

In 3 simple sections, you’ll find where to start, what the best bike size is for the skill level of your kid, and other important things to consider.

Read on! And let’s clear the possible doubts and roadblocks that you may experience in your quest for your kid’s new ride. 

Table of Contents

Kids bike size guide: Where to start?

Manufacturers normally size their bikes by wheel size, height, and age, and yes they are important things to know but they only will give you a ballpark idea of the bike size your kid needs.

To get the perfect bike size for your kid you’ll need to know their height, inseam length, and their riding skills as this will determine the right seat height for them to feel comfortable and be safe.

Measuring the inseam length is quite easy, here is how:

  1. Have your kid stand against a wall with their feet slightly away from one another
  2. Place a hardcover book between the kid’s legs. The spine of the book under the crotch.
  3. Imagine that the book is the bike seat, so the book should firmly touch the crotch.
  4. Make sure the book is leveled with the wall and measure from the spine of the book to the ground. Done, this is your kid’s inseam!

Now with the measures well taken and written somewhere, place it into the kid bike size chart:

Wheel SizeInseam LenghtHeightAge
12″15″ – 18″
38cm – 46cm
36″ – 39″
92cm – 96cm
2 – 3
14″15″ – 20″
36cm – 51cm
37″ – 44″
94cm – 112cm
2 – 4
16″16″ – 22″
40cm – 56cm
41″ – 48″
102cm – 123cm
4 – 6
20″19″ – 25″
48cm – 63.5cm
45″ – 54″
114cm – 131cm
5 – 8
24″23″- 28″
58.5cm – 71cm
49″ – 59″
124cm – 150cm
8 – 11
26″25″ and up
63.5cm and up
56″ and up
142cm and up
*Kids bike size chart may vary from one manufacturer to another use this one only as a reference

Don’t panic if your kid falls between several bike sizes, in most scenarios, this will be the case! And it’s great, cause now we are going to look into the kid’s riding skills and seat height to finally choose the right size for him/her.

Quick note: Seat height is measured from the ground and to the top of the seat.

Training wheels

I’m not going to get political about using or not training wheels, in the end, it is your kid, you know it better and it’s your choice. In my opinion, they should only be used if the kid feels extremely insecure on the bike, cause in general, they delay the process. Also, everyone should go at their own pace and riding a bike should be a fun experience.

For kids that are on training wheels, seat height doesn’t matter much as the wheels will keep the balance of the bike for the kid and they can tiptoe the floor without a problem.

The confidence of the kid is what will determine the saddle height, if your kid is confident and want to go faster you can set the seat height higher up to 3 inches than their inseam, in contrast, if your kid is calmer and is just getting the feel of their new bike set the seat so they can put their feet flat on the floor.

Careful though, if your kid still brakes with its feet make sure the seat is set so he or she can do it. Doesn’t matter if he wants to go fast as hell, teach him to use the brakes first.

First bike off training wheels

At this skill level, the seat height should be equal to the kid’s inseam length, meaning kids should be able to put their feet flat on the floor while seated. 

So here you want to choose the wheel size that allows the seat height to match your kid’s inseam. 

Experience riders

Experienced young bike riders can operate a little differently. Experienced riders should be able to use the brakes. Their enhanced comfort level allows them the luxury of seating on the bike’s saddle with the tips of their toes touching the floor. As a result, the overall seat height of an advanced bike rider can be set two to four inches above the inseam. This scenario allows for the appropriate leg extension for the rider.

Let’s put an example bike size for a 7 years old kid with an inseam of 20 inches, in this case considering he is an experienced rider the best fit will be a 24-inch bike.  

Other things to consider: Weight, Tires, Wheelbase…

Not all bike manufacturers size their bikes similarly, there are major factors to look at before buying your kid its new ride. Things like stand-over height, minimal and maximal seat height, and supported weight.

To get the most value out of your bucks and for kids’ safety, of course, you should pick a bike that the minimum seat height equals your kid’s ideal seat height as we saw in the skills level section. Cause it is a well-known fact that kids grow. What you didn’t know? And when they do you have spare margin by mounting up the seat height and your kid will enjoy longer his loved ride.

Did you ever borrow your big sister or brother’s bike and fell on the top tube? If yes Ouch! I did and it was not funny at least for me. To avoid this happening to your kid you want a bike that the stand-over height is at least your kid inseam measure, it is better if there are 1-2 inches between the bike frame and their crotch.

Supported weight is a factor that gets overlooked but is a major lookout, cause you don’t want the bike breaking in the middle of a steep descent, so make sure the bike you pick can handle more than your kid weight. 

The finish line

Taking your kid’s measures correctly and knowing their experience level are the keys to completely nailing your kid’s bike size.

Do not forget to always check the kids’ bike size chart for the brand you are looking to buy as there may be differences from brand to brand or model to model.

Safety bike equipment for kids is a complete must and you should consider it when buying your kid’s new bike.