Bike Sizes For Kids – The Ultimate Guide

Written by Dan Paul
Updated on
bike sizes for kids

This article focuses on bike sizes for kids. It will help you to understand and teach how to choose the right size bike for your kid. 

Around 15 years ago I was purchasing the first bike for my kid and I made several big mistakes. I had to learn from my costly mistakes. I wrote this article to share my knowledge, so you can avoid the mistakes I made. 

There are several ways of determining the right bike size for your kid. Even so, I recommend focusing only on the chart where the inseam is taken into consideration. 

Here are the charts for kids’ bike sizes:

When kids are ready to learn how to bike?
Why is kids’ bike size important?
Kids’ bike size by age and wheel size
Best and most accurate method to determine bike size for kids (based on inseam)
How do you know that a new bike is a right size?
Closing thoughts

Keep reading to find out about bike sizes for kids. 

When kids are ready to learn how to bike?

The average age for kids to learn how to bike is between 3 and 7 years old. Several factors can change the outcome as children are all different.

Some might master their balance before hitting 3 years old. For example, my friend’s son started using his balance bike before he turned 2. A balance bike is a perfect way to start building confidence and prepare balance skills for a pedal bike. 

Most kids who were using balance bikes before pedal bikes can avoid training wheels. This is due to trained balance and better confidence. 

Why is kids’ bike size important?

Correct bike size for your children is crucial due to handling, safety and positive first impression. A bigger bike is harder to handle and will make the whole experience less enjoyable. If the first impression is negative, it can ruin the whole experience and dent confidence. 

A bad experience might bring unreasonable fear and bike avoidance for years. 

Kids bike size by age and wheel size 

Kids and adult bikes are sized differently. If adult bike fitment is about frame size then for kids bikes are the most important wheel size. 

There are two ways to determine the right bike size for your kid. The first one was used at least 30 years ago, but for the sake of an example, I will list this chart. Keep in mind that it’s not accurate and I don’t want you to rely on it. 

The problem with this approach is that kids are very different. There are tall and small kids and they can be the same age. 

Wheel sizeAgeHeight (in)Height (cm)
10”22’0″ – 3’1″85cm – 95cm
12”3-43’1″ – 3’3″90cm – 100cm
14”4-53’3″ – 3’7″100cm – 110cm
16”5-63’7″ – 3’8″110cm – 115cm
18”6-83’7″ – 3’8″115cm – 120cm
20”9-114’0″ – 4’5″120cm – 135cm
24”11-144’5″- 4’9″135cm – 145cm 

Best and most accurate method to determine bike size for kids (based on inseam)

This is the chart I recommend for you. Based on this information you can determine the right bike size. This approach is fairly accurate and allows you to buy a bike or bikes without seeing them in person. 

Bike inseam is measured from the top of the crotch to where your kids’ feet touch the ground. This is the imitation of a bike saddle height. Your little one should be able to put one foot completely down while on the bike. 

How to measure inseam? 

  1. Let your child stand against a wall with shoes he/she will ride a bike.
  2. Let them stand with their feet shoulder width.
  3. Place a book between (preferably hardcover) their legs. Raise it against the crotch.
  4. Measure from the ground to the top of the book (crotch level) to determine the bike inseam.

Sometimes kids don’t want to stay still as they are very busy little humans. If you experience such difficulty then you can mark down the book placement with a pen. 

Another note is that bike inseams are different from pant inseams, so make sure you push the book against the crotch. But not too hard. 

Wheel sizeAgeInseam (in)Inseam (cm)
10”212” – 14” 30cm – 35cm
12”3-414” – 17”35cm – 42cm
14”4-516” – 20”40cm – 50cm
16”5-618” – 22”45cm – 55cm
18”6-820” – 24”50cm – 60cm
20”9-1122” – 25”55cm – 62cm
24”11-1424” – 28”60cm – 72cm

How do you know that a new bike is a right size? 

Do you worry about whether you purchased the right bike? Few quick points that will boost your confidence as a parent. 

  • Hands should easily reach the brake and gears.
  • Brake levers should be easy to pull.
  • Sitting on the saddle, both feet should reach the floor for stability
  • When one foot is placed on the floor and another on the pedal, the pedal leg should be bent slightly at the knee (place pedal in the bottom of its stroke, 6 o’clock)
kid riding a perfect sized bike

Closing thoughts 

Correct bike size for your kid is crucial. It will help to build confidence and ensure smooth progress. 

Don’t rush your kids into bigger bikes (even one size up is too big) as they are harder to handle. Also, please don’t forget about helmets as the security and the well-being of children are most important. 

Now wonder what would be the correct bike size for a parent? Read my article about bike frame size charts for adults. 

Photo of author


Dan is the owner of Sportscalorie. His mission is to educate people through his own experience. He proudly says that cycling changed his life.