Realistically, What Size Bike Do I Need for My Child?

While it could be easy to buy an adult-size bike, especially when you are of medium height, getting a picture-perfect kids’ bike is often challenging. You’ve to ask, what size bike do I need for my child?

Your child can ride a 12-inch, 14-inch, 16-inch, 18-inch, 20-inch, or 24-inch, depending on age, inseam, and height. So, it’s critical that you consider at least two of these factors to get the most befitting kids’ bike sizes. 

I’ll shortly provide a quick size chart to help you find a bike size that matches your kid. I’ll even help you calculate their inseam and height, as the two factors are critical in sizing your kids’ bike size. 

We will, after that, look at the various ages and their ideal bike size. Here’s what you’ll learn:

  • What bike size does your child need?
  • How do you determine what size bike your child needs?
  • How do you size a BMX bike?
  • What are the various kids’ bike types on the market?

Let’s dive in!

what size bike do I need for my child

 Kids Bike Sizes Chart

To get the correct bike size for your child, you must consider their age, height, or inseam. But to ensure the bike fits them perfectly, weigh at least 2 of these factors, bringing us to the kids’ bike size chart below. 

Wheel Size (Bike Size)Age Height Inseam (inches)
12-inch 2 – 3 years 2´10´´ – 3´4´´14 – 17″
14-inch 3 – 4 years 3´1´´ – 3´7´´16 – 20″
16-inch 4 – 5 years 3´7´´ – 4´0´´18 – 22″
18-inch 5 – 6 years 3´9´´ – 4´3´´20 – 24″
20-inch 5 – 8 years 4´0´´ – 4´5´´22 – 25″
24-inch 7 – 11 years 4´5´´ – 4´9´´24 – 28″

Understanding What Size Bike I Need for My Child

What Size Bike for 3 Year Old?

A 3-year-old has two bike options (12-inch and 14-inch) depending on height and inseam. Go for a 12-inch kids’ bike if the 3-year-old is 2’10” – 3’4″ tall or has an inseam of 14 – 17 inches.

However, go for a 14-inch bike if the child is 3’1″ – 3’7″ tall or has an inseam of 16 – 20 inches. 

What Size Bike for A 4-Year-Old?

You can either go for a 14-inch or 16-inch kids’ bike for a 4-year-old, depending on their height and inseam. A 14-inch bike suits a 4-year-old who is 3’1″ – 3’7″ tall and those with an inseam of 16 – 20 inches. 

Meanwhile, a 16-inch kids’ bike suits a 4-year-old who is 3’7″ – 4’0″ and those with an inseam of 18 – 22 inches. 

What Size Bike for A 5 Year Old?

There are three bike size options for 5-year-olds (16-inch, 18-inch, and 20-inch), depending on how tall they are. A 16-inch kids’ bike suits five-year-olds who are 3’7″ – 4’0″ tall and those with 18 – 22 inches inseam. 

On the other hand, an 18-inch kids bike suits 4-year-olds who are 3’9″ – 4’3″ tall or with an inseam of 20 – 24 inches, while a 20-inch bike is ideal for those who are 4’0″ – 4’5″ tall or with an inseam of 22 – 25 inches. 

What Size Bike for 6 Year Olds?

6-year-olds can ride an 18-inch or 20-inch kids’ bike depending on height or inseam. Go for an 18-inch kids’ bike when your 6-year-old is 3’9″ – 4’3″ tall or has an inseam of 20 – 24 inches. 

In contrast, go for a 20-inch if the kid is 4’0″ – 4’5”tall or has an inseam of 22 – 25 inches. 

What Size Bike for 7 Year Olds?

A 7-year-old can ride a 20-inch or 24-inch kids’ bike, depending on their height. A 20-inch kids’ bike suits seven-year-olds who are 4’0″ – 4’5″ tall and those with an inseam of 22 – 25 inches. 

In comparison, a 24-inch kids’ bike best suits seven-year-olds who are 4’5″ – 4’9″, especially those with 24 – 28 inches inseam. 

What Size Bike for 8 Year Olds?

Consider 20-inch or 24-inch kids bike for an 8-year-old, depending on their height and inseam. On the one hand, a 20-inch bike suits 8-year-olds who are 4’0″ – 4’5″ tall, more so those with an inseam of 22 – 25 inches. 

On the other hand, a 24-inch bike size suits 8-year-olds who are 4’5″ – 4’9″ and those with an inseam of 24 – 28 inches. 

What Size Bike for 9 Year Olds?

9-year-olds should ideally get a 24-inch bike, especially if they are 4’5″ – 4’9″ tall and have 24 – 28 inches inseam. If the 9-year-old is slightly shorter than 4’5″ or has an inseam of marginally less than 24 inches, you can get a 20-inch bike. But overall, a 24-inch bike is the most ideal. 

What Size Bike For 10 Year Olds?
A 10-year-old will most likely ride a 24-inch kids’ bike comfortably. They have to be 4’5″ – 4’9″ tall or have an inseam of 24 – 28 inches. But if the child is shorter than 4’5″, you can get them a 20-inch bike. 

What Size Bike for 12 Year Olds?

12-year-olds require a bike that’s slightly bigger than what the kids below their age need. You can, however, start with a 24-inch bike if the kid is 4’5″ – 4’9″ tall or has an inseam of 24 – 28 inches. But if they are taller, go for a 26-inch bike. These bikes suit kids who are taller than 56 inches. 

What Size Bike for A 14 Year Old?

A 14-year-old will most likely ride an adult bike. That means you can consider anything from 24 inches and above. 24-inch bikes are best for 14-year-olds who are 4’5″ – 4’9″ tall, while 26-inch suits those above 5 feet tall. 

What Size Bike for A 14 Year Old

How Do You Know What Size Bike a Kid Needs?

You know what size bike a kid needs by considering these factors:

  • Age of the kid 
  • Their height 
  • Their inseam (inside leg) length

Let’s discuss them. 

Kids’ Bike Sizes by Age

You can get anything from a 12-inch kids’ bike to a 24-inch kids’ bike for your child, depending on their age. That brings us to the kids’ bike sizes chart below. 

Bike Size (Wheel Size)Preferred Age 
12-inch 2 – 3 years 
14-inch 3 – 4 years 
16-inch 4 – 5 years 
18-inch 5 – 6 years 
20-inch 5 – 8 years 
24-inch 7 – 11 years 

Kids’ Bike Size by Height

You can also determine what bike size to get your child using their height. Here’s how to measure their height. 

Ask the child to take off their shoes and have them stand on an even surface, preferably against the wall 

They should stand straight, legs apart slightly, and face forward 

Measure the distance from the head to the toes and use the figures alongside the kids’ bike size chart below to determine what size bike to get;

Bike Size (Wheel Size)Preferred Height 
12-inch 2´10´´ – 3´4´´
14-inch 3´1´´ – 3´7´´
16-inch 3´7´´ – 4´0´´
18-inch 3´9´´ – 4´3´´
20-inch 4´0´´ – 4´5´´
24-inch 4´5´´ – 4´9´´

Kids Bike Size Guide by Inseam 

This is probably the most accurate bike sizing method for kids. The child should stand over the bike comfortably and steer it. That’s only possible if their inseam (inside leg) matches the bike size. 

Follow these steps to know your kid’s inseam length:

  • Ask your child to stand straight, feet shoulder length apart and facing forward, just like in the first case
  • Place a textbook between the legs and gently move it up until it reaches the crotch
  • Measure top-of-the-book-to-the-ground distance, which represents the kid’s inseam 
  • Use the figures alongside the kids’ bike sizing chart below and find your kid the perfect bike size
Bike Size (Wheel Size)Inseam 
12-inch14 – 17″
14-inch 16 – 20″
16-inch 18 – 22″
18-inch 20 – 24″
20-inch 22 – 25″
24-inch 24 – 28″

BMX Bike Sizing Guide for Kids 

BMX bikes are sized differently from other kids’ bikes. So, you won’t be using the sizing charts shared above. Ideally, BMX kids’ bikes come with 20-inch wheels, which means you cannot size them according to the wheel size. 

Their difference is their frame size, where we have five options for racing BMX. Here’s a BMX bike size chart to use in that regard:

BMX Bike Size Preferred Age Preferred Height
Micro Mini Up to 5 years 3´6´´ – 4´0´´
Mini 5 – 7 years 4´0´´ – 4´4´´
Junior 7 – 9 years 4´3´´ – 4´7´´
Expert 9 – 11 years 4´6´´ – 5´5´´
Expert XL10 – 13 years 5´3´´ – 5´7´´

One BMX bike that comes in various sizes to match kids of different heights and sometimes adults is the Mongoose Legion Freestyle BMX (Check on Amazon). 

This entry-level kids BMX is a freestyle BMX that your kid can use for stunts anywhere outdoors, especially on the streets. It’s ruggedly built to handle all the physical aggression you throw at it. 

How Do You Know What Size Bike a Kid Needs

Different Types of Kids’ Bikes to Consider

Except for BMX bikes (which I discussed earlier), kids’ bikes come in 3 types as follows:

1. Balance Bikes 

Balance bikes are designed to help your kid learn to balance on a bike independently and steer it. That’s critical even before they know to pedal. 

So, these bikes ideally don’t have pedals and are generally best for kids between 2 and 5 years. One fantastic choice is the KRIDDO Toddler Balance Bike (Check on Amazon).

2. First Pedal Bike 

Your kid will need a pedal bike once they learn to balance and outgrow a balance bike. These bikes come in 14- and 16-inch options for kids 3 – 5 years. 

Pedal bikes help kids learn to pedal independently and will most likely feature training wheels. One fantastic choice is the RoyalBaby Freestyle Premium Kids Bike (Check on Amazon). 

3. Off-Road Kids Bike (or Hybrids)

Once your kid outgrows a pedal bike, most likely when they are older than five years, they’ll need an all-terrain bike. 

That’s where an off-road bike or hybrid comes in. These bikes come with a wheel size starting from 20 inches, and a perfect example is the Huffy Kids Hardtail Mountain Bike (Check on Amazon). 

This hardtail mountain bike suits kids 5 – 9 years or about 44 – 56 inches tall. The hardtail is built to take in the rough neighborhood. 

In Conclusion, What Size Bike Do I Need for My Child?

Generally, you can get your child any bike from 12 to 24 inches, depending on age, height, and inseam. Remember, we are talking about the kids’ bike wheel size, which starts from 12 inches. 

But to ensure you get the right size, consider at least 2 of the shared factors (age, height, and inseam).