
Choosing the right size bike for your child depends on lots of different factors, including height and ability. So, what size bike is best for 5-year-olds?
Our eldest boy Sonny started off on a balance bike around his second birthday, moved on to a fairly cheap starter bike with 14-inch wheels when he was almost 4, and by the time of his fifth birthday was ready to move up to something a bit more advanced.
Here’s our guide to picking the right bike from our experiences – but remember they won’t be the same for everyone!
Get measured at a bike shop
Most adult bike sizes are measured by the frame, but with young kids the main measurement you’ll see is wheel size. So that’s the bit you need to get right first.
I sat Sonny on a few bikes in a few shops to get a feel for the right size, and common sense told me that 18-inch was probably the right way to go. But he’s a confident and fairly strong rider for his age so I decided to take a bit of a gamble.
I spotted the Original 100 Kids’ 20″ hybrid bike on the kids’ section of the Decathlon website and decided to take a gamble. Despite being described as for 6 to 9-year-olds, Sonny snuck into the bottom end of the recommended height range by a few centimetres at 118cm tall. So it seemed a risk worth taking.

Be guided by your child’s ability
There’s no point buying a fancy, expensive bike if your child hasn’t mastered the basic skills of cycling yet. They won’t be confident enough to handle it. The Decathlon Original 100 Hybrid isn’t a technically difficult bike to ride, but it’s got thin tyres and is designed for flying along at a decent speed. It’s the perfect urban bike for confident 5-year-olds, but you may want something with chunkier tyres if your kid is still a bit wobbly.

Match the bike to where you’ll ride it
Don’t buy a mountain bike for your child if you’re only planning to pedal to school or along pavements to the local park. And likewise, don’t buy a hybrid bike if you’re planning to do loads of off-roading. For us, the hybrid is perfect because we do around 1.5 miles every day on a little loop to school and back, which takes us on pavements, roads and a smooth tarmac track through the park. And it works fantastically.
If you’re unsure – aim for the larger option
If your child looks too small for one wheel size but not quite ready for the next one up, the sensible bet is to go for the larger one. After a few attempts they may find the bigger bike is fine after all. And they’re only going to grow taller and stronger, so opting for the smaller option could mean you’re back at the bike shop a few weeks later. This is a bit of a balancing act though, because if you go way too big and your child doesn’t like the bike, you may put them off the idea of cycling altogether.

So… what size bike is best for 5-year-olds?
For us, the answer was a bike with 20-inch wheels. The Decathlon Original 100 Kids’ 20″ hybrid bike has been perfect so far. We use it every day to cycle to school, and have even ridden it off-road on grassy tracks along our local river.
I’ll be honest, when I first saw Sonny straining to get onto the saddle on the morning of his birthday, my heart sank. But he quickly figured out how to push himself off and stop, and once he got the bike moving he’s never looked back. He mastered it in about 5 minutes!
But like I’ve said above, that won’t be the same for all 5-year-olds. From our experience, it seems like something between 18-20 inches for the wheel size seems about right. The following advice on the Decathlon website is slightly less cautious though, recommending that 14-16″ wheels are the best option for kids aged 4-6.
The key thing though, as with everything you buy for kids, is trying a few different options and finding the one that works best for them. Because all kids are 5-year-olds are frustratingly different!