Kids bike sizing guide

Mar 7, 2022

Traditionally, children’s bikes are measured by wheel size and categorised by age range. However, if your child is smaller or larger than the average size for their age, this system may be misleading and not applicable. It is, however, important that your child’s bike fits well. Getting a bike too small for your child could mean that they outgrow it quickly. Too big and it may be dangerous and difficult to ride.

As a general rule of thumb, the bigger the wheels on a child’s bike, the bigger the bike. This is because, with larger wheels, the saddle will be further from the ground. If the bike is too big, your child might struggle to reach the floor or even mount the bike. A larger bike will also be longer in order to accommodate for the bigger wheels. Again, when too big, your child might struggle to reach the handlebars.

If your child looks between sizes, and both bikes are safe and comfortable, we would recommend settling for the larger one. As they’re continuing to grow, they will fit the new bike perfectly in little time at all and riding a larger bike will improve their confidence.

Buying online or measuring from home

If the bike for your child is a surprise, perhaps a gift from Santa or something for their birthday, you may need to choose one without them present. If this is the case, the most accurate way to achieve the correct bike size is by measuring them, particularly their height and inseam.

For their height, simply measure the distance from the floor to the top of their head while they’re standing. For their inseam or inside leg length, measure the distance from the floor to their crotch. Once you’ve got these measurements, take a look at our handy table below. This gives an estimation of the bike size appropriate for your child. Again, if your child appears to be in-between sizes, we would recommend going for the larger one.


If you’re unable to measure them, using their age as an indicator of the bike size they’ll need is an alternative method. As this is a little less reliable, therefore we’d strongly recommend popping into one of our stores to view the bike for yourself. Our highly trained staff will be more than happy to help select the perfect bike for your little one.


Buying in-store

If you are able to bring your child into a store, this is the most reliable way to find the best fitting bike and they’ll even be able to pick their favourite colour and style! Our staff are fully trained to measure and fit your child to their new bike. To find your local Cycle King & Hawk Cycles, use our handy store finder.

When measuring your child for a bike, there are a few essential things to ensure. Firstly, ask your child to stand over the bike’s top tube. There should be a clearance gap, it is essential that this is present for their safety while on the bike. If there is no gap, the bike is too big and dangerous to ride.

It is important to also check that the bike is not too small, this can be achieved through the heel-on-pedal method. Ask your child to sit on the bike and put their heel on the pedal. If the seat is at its maximum extension and their leg is bent, then the bike is too small.

Generally, children are more comfortable sitting upright than adults. Therefore, you should ensure that they can comfortably reach the handlebars and apply the brakes with ease. If installed within the bike, check that they can also change gears easily, if they’re struggling to reach, the bike is too big.

Finally, before you buy any boys’ or girls’ bike, confirm that it is of a manageable weight for your child. Surprisingly, many children’s bikes tend to weigh the same or more than adult bikes. Pick up the bike and make certain that it isn’t too heavy for your little one to ride and manoeuvre.