Kids Bike
Size Guide

Getting the right size bike is always a really important consideration, and it's even more important when it comes to kids' bikes. Children need their bikes to be the perfect fit so they can learn to cycle safely and comfortably - and develop that all-important love of cycling.

Fortunately, there are a few simple ways to understand how bike sizes for kids work, so you can find the perfect bike for your kid. We've put together a handy guide to get the right bike size for your little ones and children who are growing up too soon!

How to measure a child for a bike

We always recommend measuring your child before buying them a new bike. Having the wrong size bike can be uncomfortable and will make learning to cycle more difficult. Age isn’t always the best indicator for a straightforward bike measurement, as children are all different sizes and grow at different rates.

Because kids come in all shapes and sizes (much like bikes), there is no “normal” leg length or height for each age category. It’s difficult to suggest the “average size bike for an 11-year-old”, or “the right bicycle size for a 9-year-old boy”, because everyone is shaped differently!

To find the right size bike, inside leg measurement is usually the easiest way to figure out fit. Here are a few super simple steps to follow to ensure accuracy when figuring out the right bike size for kids:

Step One

To measure the inseam or inside leg, stand your child up with their back against a wall.

Step Two

Have them hold their legs together, and then place a book between their legs, as high as comfortably possible.

Step Three

Use a pencil or tape to mark the top of the book. Move them away from the wall and measure from the top of the book to the floor.

Then, measure their height…

Step One

Stand your child in their socks against a wall.

Step Two

Measure them from the floor to the top of their head.

You can then use the table above using these measurements to find the perfect size bike for your child based on their height and age. Of course, there may be some slight differences between the two - sometimes kids are tall or short for their age, which is why it's so important to take actual physical measurements.

The minimum inside leg length refers to the saddle being at its lowest setting and the maximum inside leg length is the highest setting. By choosing the minimum leg length, your child can grow with the bike and it may last a little longer in regards to fit. By ensuring you’ve got the correct sizes, your child will safely and comfortably be able to get their feet on the ground.

How to work out kids' bike size

Kids' bike sizing is determined by the wheel size, or diameter to be more precise, whereas adult bikes are sized by the frame size and seat height. The smallest kids' bikes - so likely the first bike you'll be looking at for your little one - start at 12-inch for balance bikes, and our Raleigh kid's bikes go up to 26-inch wheels, which are generally the right size for kids aged 9-11.

There are also different bikes that suit different stages. Balance bikes - bikes without pedals - are ideal for a kid's first experience on a bike to get them used to the posture and experience. After they get the hang of it, you can then think about moving onto a junior bike with stabilisers.

Bike sizes for children by their age

Although it can be difficult to judge buying a children’s bike based on their age, their ability to ride a bike also varies as they grow up. Children develop at a different rate to one another, so we have summarised the type of kids' bikes suitable, based on their age group. Of course, as they grow they'll likely need to move up to the next size bike, but measuring will help make sure you choose the right one for the best comfort and safety.

For more in-depth information on making the right choice, check out our kids' bike buying guide.

Bike sizes for a 4-year-old

For the little ones, based on their ability, there are three types of bikes suitable, Molli, POP and Balance Bikes, built at either 12 or 14 inches. If you’re not sure what balance bikes are, they’re designed without pedals to help your child focus on balancing on a bike and riding without assistance. Again, the Molli and POP 14 range both come with removable stabilisers so the bike will grow with them as their ability develops.

Bike sizes for a 5-year-old

For a five-year-old child, the Raleigh Molli and POP range are all suitable. These styles of bikes cater to children who need a frame sized between 14 and 16 inches. If your child needs additional support riding to help improve their confidence and balance, the Molli and Pop 14 styles both come with stabilisers, which are easy to remove once your child feels more coordinated.

Bike sizes for a 6-year-old

Wondering what size bike is best for a 6-year-old? It goes without saying, but typically the older the child, the bigger the bike they need. However, it's always really important to take accurate measurements to make sure the wheel size is correct for your child. Our Pop children’s bike range has a selection of frames suitable for a 6-year-old, ranging between 18 inches and 20. Each bike size is designed with an adjustable saddle to accommodate your child as they grow.

Bike sizes for 7 to 9-year-olds

Moving up to a 20 inch wheel can be a big step up as it generally marks the transition into junior bikes - essentially the step between kids' bikes and adult bikes. Again, bike size will depend on height, so make sure to check the inseam measurement. Typically, the right bicycle size for 7-year-old cyclists is usually something with an 18-20 inch wheel. If your child is in between sizes it might be worth thinking about opting for a larger wheel size for when they grow.

Bike sizes for 10 to 12-year-olds

As your child grows taller you'll notice them needing larger bike sizes to fit. 24 inch and 26 inch wheels are still classified as junior bikes and are usually the last transition size before tweens and teens move into adult bikes.