How do I Measure my Child’s Inseam for Bike Size?

How do I Measure my Child’s Inseam for Bike Size?
How do I Measure my Child’s Inseam for Bike Size?

Your kiddo needs a ride. You walk into a store to buy, and there are bikes all over it. It’s obvious to be confused to select one that best suits your kid size-wise.

The storekeeper will suggest bikes based on your kid’s age, but you cannot be sure that the bike will fit. You don’t know where to start from.

This article will guide you through all the steps to take in sequential order so that you will have no hesitations and dilemmas for selecting the right sized bike for your kid.

There are no standards for sizes when it comes to kids’ bikes. Generally, manufacturers categorize kids’ bike sizes based on their wheel size.

But the problem is only wheel size cannot determine the appropriate size for your kid.

Child's Bicycle
Child’s Bicycle (Source:

Other factors that exist to help select the bike for your kid such as their age. But all children grow at a different pace.

Kids of the same age can be of different heights. Thus, age also cannot be considered a promising determinant for bike size.

Hence after a lot of research and practice, a constructive trick has been devised to do so. The inseam length of the child is measured to find the best fitting bike.

The inseam is the length from the crotch to the leg of the kid. The measurement should be taken correctly otherwise, you may end up getting either a smaller or bigger bike size for your kid.

Ways to find Inseam Length for Kids

You can follow these exact procedures to find the precise inseam length of your kid. Don’t skip any steps.

And this technique is recommended by professional riders and kid’s bike manufacturers as well.

  • Let the kid stand over the wall in an upright position. The feet should be close to each other like that of the kid shown in the figure below. 
  • The feet should be flat touched to the ground with their shoes on because they will be wearing shoes while riding the bike. So, this will give you the exact inseam of the kid which includes the height of the shoes.
  • Then place a book (having a hardcover) in between the legs and slide it up until it reaches the crotch of the. The book should touch the crotch like the seat touches the crotch of the kid while they are on a bike.
  •  After hitting the crotch, the tip position of the book that touches the wall should be marked vertically with a marker.
  • Finally, a tape can be used to measure the length from the marked point on the wall to the ground which will give you the inseam length of the kid.

This process can give the inseam length of your kid pinpoint accuracy if done rightly.   After you are aware of the Inseam calculations, you can now proceed to look out for bikes. 

Can I measure my Child’s Inseam from his/her Clothes?

If you are thinking about gifting your kid a bike and you don’t want to ruin the surprise, here’s another way to find the best fitting bike for them.

Find a pair of jeans that fits the kid perfectly. Put the pant down on the floor or bed where it does not shrink. Now place the tape from the crotch and roll it down to the bottom. 

You got the inseam length. Don’t forget to think about the shoes as well.

Think about the heels of the shoes of your kid. You should consider and add the height of the shoes to the previously calculated inseam.

This idea might not work well if the pant is not selected wisely. The pants are more likely to shrink, which can even give a false length.

Although, the seat heights can be adjusted. It can be challenging for the kid if the difference is minimal and the inseam length lies out of the minimum-maximum seat heights range.

The best alternative for this would be taking the measure of the kids as mentioned in the first point.

You can make up lies saying that the measure is for their clothes or school uniforms. The bike is surely an expensive thing to buy so, choose your option wisely.

Evaluating Inseam Length to Select a Bike Size 

After you have the inseam measurements, the next thing to consider is the bike’s seat height. This is the height of the seat of the bike from the ground.

Compare the inseam and seat height of the bike you are going to get for your kid. Get the best one that matches the inseam of your kid.

Right Measurement of the Bike Accessories
Right Measurement of the Bike Accessories is necessary to assess while buying (Source:

Look out for the standover heights and the min/max range of seat heights. You should take time and have a fine look at all the available bikes and analyze properly all these essential features discussed below.

Here is a chart that will help you determine the size of your kid’s bike based on the inseam, age, and wheel size.

Age (years)Inseam (inches)Wheel size (inches)
2 – 314 – 17” (35-42 cm)12”
3 – 4 16 -20” (40-50 cm)14”
4 – 518-22” (45-55 cm)16”
5 – 820-25” (55-63 cm)20”
7 – 1124-28” (60-72 cm)24”
Chart showing Child’s Inseam Size

It is not ideal for falling the child’s inseam between these to make an easy decision. Suppose the inseam of your child is 17,” and it falls in the first two inseam ranges.

It won’t be obvious to decide which one will suit your child the most. At this point, the strength and capability of the kid to ride need to be inspected.

If the child is starting to ride, you should probably go for the first possible with a wheel size of 12 inches.

But if the kid is already an experienced rider, then the second possible scheme is doable in such instances.  

Knowing the Wheel Size

Not all the bikes with the same wheel size will fit the same kid. Different brands have different seat heights and standover heights. Two 14” bikes from different companies can vary greatly in overall shape and size.

The standover height is another significant aspect to observe while buying a kid’s bike. The length of the bike’s tubes, where the kid can lean on while standing with the bike, to the ground is the standover height.

The inseam should at least be equal to the standover height to allow comfortable riding for the kid.

Inseam Differences with Various Types of Bikes

The ability to operate a bike depends on how easily the child can touch the ground in the seated position. The expertise of riding is directly proportional to the length added to the inseam of the child.

For a balance bike preferred for a newbie rider, the inseam should not be less than the minimum Seatpost height. 

A bike with a Seatpost height up to 1 inch greater than the kid’s inseam in the first pedal bike.

Learn about How to size a kid’s Bike while buying from this youtube video.

This enables the child to touch the ground with the tip of the feet, which will not be much of an obstacle for the kid for whom balancing the bike is not that challenging. 

Finally, when the kid has passed some productive riding years, and it is time to detach the training wheels, they can now progress to a bike with the lowest Seatpost height, which is 1 to 3 inches more than their inseam length.

But if the minimum Seatpost height crosses 3 inches plus the inseam length, the ride can be quite troublesome as the child might encounter difficulties reaching the pedals with ease.

Such complications can even hurt the kid, so the parents need to be alert about such points.

In general, well-reputed brands provide information on the minimum and maximum Seatpost heights of their bikes available in the market. You can find information regarding this on their official website. 

Tools to help with the Measurement of the Inseam

The development of humans has grown to the point where tools are developed to effectively facilitate any tasks or processes.

Likewise, some bike manufacturers also have designed tools to help pick the correct bike for a kid.

They provide a chart with inseam and bike models that will suit your kid, such as the Woom size chart and Guardian Bikes Size Assisting Tool.

The kids can outgrow the bike size quickly or slowly.

So make sure to consider and look out for options and conduct inspections on the wheel size and min/max Seatpost height of the bike and compare with your child’s inseam so that you can find a decent ride for your child.

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