How to choose the right size bike for your child’s age

Whether your child is new to cycling, or has been a confident pedaller for years, when the time comes to buy them a new bike, figuring out what size to get them can be a daunting task. That's why we've created this guide to show you how to choose the right size kids' bike for your child's age group.

The Cycle Sprog team is made up of passionate cyclists and parents alike. We know what a struggle it can be to find the right size bike for your child. It can be less so for very young children, as their heights tend to vary less within their age group, but as children grow and get older, the variation in their size can make it harder to discern the best size bike for their needs.

Having been writing about family cycling and offering advice to parents since 2012, we can see that while kids’ bikes are generally divided into wheel size categories (from 12-inch balance bikes to 26-inch bikes), unless they know what wheel size their child needs, parents more than likely search for the right bike based on their child’s age instead. 

This may seem fine, but just like a size 14 dress from two different brands will fit the same body differently, different bike brands will vary in their sizing and age estimates. If you search purely by age, you could end up choosing between two bikes that wildly differ in size, and getting the size right is important. So here's how to choose the right size kids' bike for your child's age group.

Why you should search by size, not age

When children are very young (18 months-3 years old), finding the right size isn’t normally an issue. Generally a toddler will need a balance bike and for the most part, will fall into a similar height bracket to their peers.

As young as 4 or 5, children's heights can vary greatly. Growth spurts happen at different times and at different frequencies, so age doesn't always make it easy to decide which size bike they need. For example, while one 10 year old may need a 24-inch bike, another could be several inches taller and need a different size entirely. Plus bike-buying can get even more complicated when they hit 10 years and upwards, because there are even more styles of bikes to choose from!

That’s why we recommend choosing a bike based on your child’s height, rather than their size. So, the first thing you need to do is measure them. We’ve got a great guide to how to easily measure your child for a bike, if you need it.

Next, we’ve tried to make the whole process of finding the right size bike as simple as possible. Choose your child’s age from the list below, and we’ll give you all the information you need to find the right size bike for them.

A note about older learners and additional needs

Generally children can start riding their very first bike from the age of around 18 months, with the help of toddle bikes and ride-ons (more on these below).

From there they'll often move onto a balance bike at around 2 years old. 

Most kids will learn to ride a pedal bike around 4-5 years old. It might be worth taking our Learn to Ride Questionnaire to gauge whether your child is ready to start this stage.

Every child is different, though. Some children will learn to ride when they’re older because they’ve not had any interest until now, while others may need to learn later to accommodate learning needs. 

For any parents who it would benefit, we’ve got a great guide to how to teach an autistic or neurodivergent child to ride a bike. It not only explores alternative learning needs, but also has useful tips for parents teaching their child to ride a bike at an older age, where balance bikes are too small.

how to choose the right size kids' bike for your child’s age

How old is your child?

• 1 – 3 years
• 3 – 4 years
• 4 – 5 years
• 5 – 7 years
• 7 – 10 years
• 10+ years

In terms of child development, the first 1-3 years encompass a lot of change, and it all happens at different stages depending on the child. For example, the physical abilities of a child who’s just turned one, and a child who’s about to turn two are starkly different, so it’s difficult to say definitively that one age equates to one ideal bike.

Since toddlers develop at different rates, it’s really important to be patient with them and try not to force them into riding a bike when they’re not ready, or not interested. A good rule of thumb to start with is that they’re not ready if they’re still crawling.

Toddlers from about the age of 18 months can start out on a pre-balance bike (otherwise known as a toddle bike or ride-on), which has four small wheels and helps them to toddle around and develop their balance.

Or they might benefit from a very small balance bike with 10” wheels. To get started, check out our guide to the best bike for a 1 year old toddler.

From there children are usually ready to move onto a 12" wheel balance bike from about 2 years and older.   

We don't recommend stabilisers for the majority of children, but a small number may need a 12” pedal bike with stabilisers. 

Read our blog post that answers the question, does my child need stabilisers? and then take a look at our guide to the best balance bikes.

While generally at this age there can still be very little variation, it’s not completely unheard of. So, even at this age, we’d recommend you measure your child’s height before committing to a particular size bike. Feel free to use our guide to how to easily measure your child for a bike.
Once you’ve got the measurements you need, take a look at our Kids Bike Search for a range of options that will work for your child specifically.

• If their height falls within the national average, then it’s fairly likely that they’ll fit a 14” bike. Take a look at our guide to the best 14” bikes.
• If they’re slightly taller than average, we have a list of the best 16” bikes, which is the next size up.
• If they’re shorter than average, you might want to check out the best 12” pedal bikes, or the best balance bikes if they’re brand new to cycling.

If your child is brand new to cycling at this point and isn’t progressing from a 12” balance bike, then we’d also highly recommend the Kidvelo Rookie range, which converts from balance to pedal bike, meaning they can learn the same way as other children, while still getting plenty of use out of the bike when they’re ready to start pedalling later. It's also worth noting that some children at this age just prefer to continue riding balance bikes and aren't ready to start pedalling yet, which is absolutely fine and normal.

Another option if you’d prefer, is to DIY, using our handy guide, how to turn a pedal bike into a balance bike.

As we mentioned above, once children reach around 4 years old, their height can start to vary within their peer group, so it’s very important to measure them before choosing which size bike to buy. To get started, use our guide to how to easily measure your child for a bike to get their exact height and inseam length, and then you can use our Kids Bike Search to see a range of size-appropriate options for your child.

• If their height falls within the national average, then it’s fairly likely that they’ll fit a 16” bike. Take a look at our guide to the best 16” bikes.
• If they’re slightly taller than average, but not quite tall enough for the next common size up (20”), then you’ll find some in-between options in our guide to the best 18” bikes.
• If they’re shorter than average, then we recommend taking a look at our list of the best 14” bikes.

Generally 16" bikes won't come with gears, as many children at this age group aren't yet ready to start using them. That's not to say yours won't, however, as children develop at different rates. If you've got a 4-5 year-old who fits a 16" wheel bike but is ready to progress to gears, then the woom 3 Automagic is an excellent option, especially if you live in a hilly area.

If your child is brand new to cycling at this point and isn’t progressing from a 12” balance bike, then we’d also highly recommend using our handy guide, how to turn a pedal bike into a balance bike, to give them the best chance at learning to balance and steer before worrying about pedalling. For more on this, read our blog post, does my child need stabilisers?

It’s possible that your child is starting to have growth spurts by now, and since children grow at different rates, it can be difficult to say for definite which size bike is right for their age. That’s why it’s crucial that you measure them, getting their exact height and inseam (the distance from the groin to the ground) so you can check bike sizing and find something that will fit them comfortably. To help, we’ve got a guide to how to easily measure your child for a bike.

Once you have those measurements, it’ll be easy for you to use our Kids Bike Search to find a range of size-appropriate options.

Another couple of factors to consider at this stage are: the type of bike you want to buy them, and the gearing they need. Once you hit 20” bikes and above, you have more options, like regular bikes (sometimes called hybrids) or mountain bikes. This is also the stage where they'll start learning to use gears, so if you live in a particularly hilly area, for example, you should consider getting them something with a decent range so they can comfortably ride up hills.

• If their height falls within the national average, then it’s fairly likely that they’ll fit a 20” bike. Take a look at our guides to the best 20” bikes and the best 20” mountain bikes.
• If they’re slightly taller than average, they might benefit from our guide to the best 24” bikes and the best 24” mountain bikes.
• If they’re shorter than average, then we recommend taking a look at our guides to the best 18” bikes and the best 16” bikes.

If your sprog is brand new to riding a bike at this point and isn’t progressing from a 12” balance bike, then we’d also recommend using our handy guide, how to turn a pedal bike into a balance bike. This can give them the best chance at learning to balance and steer before worrying about pedalling. Kidvelo and Black Mountain also offer options for balance bikes that work for taller children. For more on this, read our blog post, does my child need stabilisers?

By this age, your child’s height will vary greatly from some of their peers, with some 7 year-olds outgrowing some 10 year-olds, and that’s completely normal. That’s why it’s impossible to say for sure which size bike is right for their age without measuring their height and inseam (the distance from the groin to the ground).

All bikes come with geometry and sizing charts so you can determine whether or not they’ll fit your child comfortably. To make things easier, follow our guide to how to easily measure your child for a bike. Then, once you have those measurements, you can use our Kids Bike Search to find a range of size-appropriate bikes for your child.

Another thing to consider is the type of bike you want to buy them, based on the kind of riding they’ll be doing. If they’re mainly riding to school and sticking to paved roads and paths, then a regular (hybrid) bike will do the trick. However if they’re heading off-road onto unpaved trails, then they might prefer a mountain bike.

• If their height falls within the national average, then it’s possible that they’ll fit a 26” bike. Take a look at our guides to the best 26” bikes and the best 26” mountain bikes.
• If they’re slightly taller than average, they might benefit from our guide to the best mountain bikes for teenagers and small adults.
• If they’re shorter than average, then we recommend taking a look at our list of the best 24” bikes and the best 24” mountain bikes.

Something else to be aware of at this point, is that at this stage bikes start to become more expensive, and the variety between different builds becomes a lot more pronounced. We'd recommend you read our article about why you shouldn't buy a REALLY cheap new kids' bike, and if you're looking for good value for money, check out our guide to the cheapest kids' bikes that are still excellent quality.

If your child is brand new to cycling at this point, then we’d also highly recommend using our handy guide, how to turn a pedal bike into a balance bike, to give them the best chance at learning to balance and steer before worrying about pedalling. For more on this, read our blog post, does my child need stabilisers?

At this point your child’s height can vary wildly from their peer group, so the first thing to do is to measure them. Bikes all come with geometry and sizing charts to refer to, so you can determine whether or not they’ll fit your child comfortably. 

Follow our guide to how to easily measure your child for a bike and then you can use those measurements to explore our Kids Bike Search and find a range of bikes that will fit your child.

Another thing to consider is the kind of riding they’ll be doing, and therefore what type of bike you want to buy them. For example if they mainly stick to paved roads and paths, and predominantly ride to school, then a regular hybrid bike will do the trick. However if they’re heading off-road onto unpaved trails, then they might prefer a mountain bike, or if they’re joining you on a club run or heading out for some fast fun, then you may want to consider a road bike for them.

• In addition to using our bike search, check out our guide to the best mountain bikes for teenagers and small adults.
• You may also benefit from our lists of the best 26” mountain bikes and the best kids road bikes.

At this stage if your child's been cycling their whole lives and are passionate about the sport, then you might find that they become very opinionated about what kind of build they want. They'll likely be learning lots of new skills and testing their limits, so we definitely recommend discussing their needs with them and finding a good option from our roundup of the best kids' bikes.

If your child is brand new to cycling at this point, then we’d also highly recommend reading our handy guide about how to turn a pedal bike into a balance bike, to give them the best chance at learning to balance and steer before worrying about pedalling. For more on this, read our blog post, does my child need stabilisers?

Closing thoughts

Hopefully with the help of this article you're feeling a bit more ready to take the next steps in your child's cycling journey.

Remember that all children are different and develop their skills at varying stages, so follow your child's lead. It's better for them to learn at their own pace and enjoy cycling for life, than to become frustrated or overwhelmed and decide they hate it.

You should have plenty of bikes to choose from once you have your child's height and inseam measurements, so be sure to make use of our handy Kids Bike Search.

Other articles you might be interested in:

• Best kids' bikes
• Cheapest kids bikes
• Best balance bikes
• Best kids' bike helmets
• Woom kids bikes - a comprehensive guide
• How to start cycling to school with kids
• Where to buy a cheap Frog Bike
• Winter cycling with kids
• Where to try family cycling equipment
• How to stop your kid getting saddle sore