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Our superlight, innovative and high-quality children's bikes offer your child no end of safe riding fun.

What is the right-sized bike for my child?

Select the right-sized kids' bike using our Bike Finder tool

Daniela Rodriguez Bonelli

The ABC of buying a kids' bike

There's a lot to think about when buying a kids' bike. Fortunately, we've done the hard work for you – you'll find all the info on key topics like weight, safety, ergonomics, brakes and product quality in >> our concise guide: Buying a bike: the must-knows.

In this particular article, we're focusing on the big S: Size. We'll look at how to pick the right size children's bike in general, and then look more closely at woom bike sizes. Read on for the answers to the following questions:

  • My child is between two sizes. Is it still worth getting the smaller one?
  • Does my child need a balance bike or can they go straight to one with pedals?
  • Can my child skip a size?

The right bike size

What exactly do we mean by the 'right' size? Easy: For every child, there's a perfectly fitting bike out there. When you buy a bike for a child, never adopt the mindset of sizing up so that your child will 'grow into it'. However minor those extra centimetres might seem, they can be the difference between frustration and fun.

For a bike to be the right size, your child should comfortably be able to reach the ground with both feet when the saddle is at its lowest without having to make any major adjustments to their posture or strain in an effort to touch the ground.

Having immediate contact with the ground on both sides of the bike is extremely important so that the rider can handle their bike safely, especially for beginners or inexperienced riders. Make sure that there's a visible gap between the top of your child's legs and the top tube when they're stood over the bike, straddling it with their feet on the ground – this is to ensure that their crotch won't hit the top tube in the event of a sudden dismount.

Hop on and take off!

Whenever possible, arrange a test ride for the bike you're considering for your child. You should be able to determine quite quickly whether your child is capable of riding a bike of that size and feels secure in the saddle. In the best-case scenario, they'll hop on and take off!


If an in-person test ride is not a feasible option, you can order the woom bike of your choice from our online shop without any obligation. You've then got 30 days to test the bike, before returning it or exchanging it if the size isn't right – the return postage is on us. You'll only have to pay for the original cost of delivery. Use our >> Bike Finder to work out what size woom bike is best for your child.

The woom Bike Finder

Our Bike Finder is a really straightforward tool: Once you've submitted a few stats about your child, the Bike Finder will suggest a woom bike that we'd confidently recommend so that your child can enjoy a safe, fun ride.

Don't be fooled by its deceptively simple-looking approach – our Bike Finder is backed by an exhaustively developed sizing system, which we've derived from an enormous body of statistical data on child anatomies and now forms the basis for all woom bikes. This means that the Bike Finder really is the best (digital) way to find the right woom bike size for your child.


If you want to discover the ins and outs of our ingenious sizing system for our woom ORIGINAL bikes, why adjustable components are so valuable on a kids' bike, and the safety benefits of having a perfectly sized bike, check out >> this article from our mini series.

When it comes to deciding what size bike your child should ride, it basically comes down to two main factors: your child's height and riding ability. Unsurprisingly, these are the same two factors that our Bike Finder takes a closer look at. Allow us to briefly explain the intricacies of these two factors so that your mind can rest easy while submitting the figures.


Once you've entered your child's age, you have a choice between 'small', 'average', and 'tall'. Now's a good time to think about how tall your child is in relation to their peers:

  • Does your child appear taller or tower above other kids of the same age? If so, it sounds likely that your child can be classed as 'tall' for their age.
  • Or is your child more or less the same size as other kids of the same age? Then 'average' is the more suitable choice.

If you're still unsure, have a look at your child's medical records or refer to an online height calculator.


Next, you'll be asked to decide between 'beginner' and 'advanced'.

  • Is your child hesitant and needs to build their confidence? Are they new to cycling or still a little cautious on two wheels? Does your child struggle to set off without a helping hand? Do they lack confidence while cornering? If so, we'd classify your child as a 'beginner'.
  • Do they find it easy to mount, dismount, set off independently, corner well, and brake effectively? If so, you should select 'advanced'.

Once you've entered all the information, the Bike Finder will suggest an appropriate woom bike and a specific size to suit your child.

Riding skills vs. leg length

Although much is made of inside leg length (or inseam) measurements, your child's actual riding ability is far more important than their leg length. Put a child with well-developed motor skills on a slightly larger bike and they will have a lot less trouble handling the bike than a child of the same size with less experience and less confidence.

What's more, the data collected on inseam measurements for kids in the same age group shows very little deviation from the average. Then, depending on the layers of clothing or your technique for taking the measurement, the actual number on the tape measure can vary by several centimetres, which means that inside leg lengths don't tell us that much after all.

That's why we've deliberately avoided specifying a leg length in our product descriptions. We are confident that our Bike Finder is the best tool out there to determine the right bike size.

However, if you are still concerned about the inside leg measurement despite our assurances, you will find an overview below showing inseam lengths that we consider minimum values for our bikes. We're pretty confident about our sizing system, but we can be flexible, too.

Taking an inside leg measurement

Here's how to measure your child's inseam as accurately as possible:

  1. Have your child stand up straight against a wall in socks and wearing trousers likely to be worn while riding a bike.
  2. Take a hardback book and place the spine of the book, facing upward, at your child's crotch with the same slight pressure that you'd get on the saddle while riding.
  3. Mark the edge of the book's spine on the wall in pencil.
  4. Now measure the distance from the floor to the marking as vertically as possible with a measuring stick or tape measure. This measurement in centimetres is your child's inseam.
  5. Now, you can compare the measurement with the minimum inseam lengths in our table.


ModelMinimum inseam lengthHeight
woom ORIGINAL 120 cm82–100 cm
woom ORIGINAL 1 PLUS36.5 cm95–110 cm
woom ORIGINAL 238.5 cm95–110 cm
woom ORIGINAL 344.5 cm105–120 cm
woom ORIGINAL 3 AUTOMAGIC44.5 cm105–120 cm
woom ORIGINAL 452 cm115–130 cm
woom ORIGINAL 563.5 cm125–145 cm
woom ORIGINAL 669 cm140–165 cm
woom OFF 450.5 cm118–130 cm
woom OFF 562.5 cm128–145 cm
woom OFF 668.5 cm140–165 cm
woom OFF AIR 450.5 cm118–130 cm
woom OFF AIR 562.5 cm128–145 cm
woom OFF AIR 668.5 cm140–165 cm
woom NOW 455.5 cm118–131 cm
woom NOW 557 cm125–147 cm
woom NOW 665.5 cm142–167 cm
woom UP 562.5 cm128–145 cm
woom UP 668.5 cm140–165 cm

Beginning with a balance bike or going straight to pedals?

It's entirely possible that your one-and-a-half or two-and-a-half year old is still not registering an interest in a balance bike, and that's totally fine. All kids are different, and they'll know when it is the right time to start riding. 

In any case, learning to ride a balance bike before learning to ride a bike with pedals is definitely a smart move; this way, they'll pick up key skills that are required for cycling, such as balance and hand-operated braking. >> In this article, we take an in-depth look at what makes balance biking so beneficial to their motor skill development and the ways in which it prepares them for riding a bike.

For children whose interest in a balance bike develops later, we have specially developed the woom ORIGINAL 1 PLUS, which comes with 14-inch wheels instead of the 12-inch wheels found on our standard balance bike, the woom ORIGINAL 1.

As these kids tend to master their balance bike relatively quickly, the woom ORIGINAL 1 PLUS comes fitted as standard with the SURFBOARD footrest to boost the fun factor. Once riders get the hang of keeping their balance and start to pick up speed and confidence, they can lift their feet to rest them on the SURFBOARD and enjoy the feeling of coasting along.

The first bike – woom ORIGINAL 2 or woom ORIGINAL 3?

The most common question that we get about bike size is where to begin. What's the right size for your child's first bike: a woom ORIGINAL 2 with 14″ wheels or a woom ORIGINAL 3 with 16″ wheels?

The general rule of not to buy an over-sized bike fit for 'growing into' is especially true when it comes to the first bike. Even if your child can confidently whiz around their neighbourhood on a balance bike, the transition to a bike with pedals involves learning how to pedal, while simultaneously maintaining balance, steering, braking, and cornering. No easy feat and kids will certainly need a sense of security and confidence to take on the challenge.

This sense of security is often lacking on a bike that is too big – picture a scene where your child is struggling to reach the ground with both feet. When using our bike finder, be aware that kids who are in the process of transitioning from a balance bike to a bicycle are still considered as a 'beginner', even though your child may be able to pilot a balance bike like a pro.


Please keep in mind that the first bike plays a major role in nurturing your child's budding love for cycling. As kids grow quickly, there is a likelihood that the bike may be too small after the first summer, but rest assured that the investment will have been worthwhile if it means that your child later finds joy and pleasure while riding their bike safely.

Thanks to the high quality of our bikes, you can expect a very high re-sale value for all woom bikes, especially if they have been used sparingly.

Skipping a bike size

So, your child is already confidently riding a woom ORIGINAL 2, woom ORIGINAL 3, or woom ORIGINAL 4 and you're wondering whether they could skip a size? Organising a test ride or making use of our Bike Finder will help you answer this question, too. 

In general, however, we advise against skipping a size. It can represent a bigger leap than you realise – particularly when you take into account that all our bikes from the woom ORIGINAL 4 and up come with gearing, which adds another dimension for your child.

For kids that are really confident on two wheels and can reach the ground on tiptoes even on the next size up, keep in mind that they won't just be riding a bigger frame but also manoeuvring more weight. In short; the smaller-sized bike will be easier for your child to handle – especially if there's a situation in which they've got to react at speed. 


We've put a huge amount of time and energy into our sizing system. It is designed to ensure that your child is riding a bike that fits them perfectly across the ages. Our progressive system tracks your child's development as a rider, and skipping sizes breaks this progression. 

All bikes from the woom ORIGINAL 4 and up are specced with our >> Vario stem, which lets the bike 'grow' by adjusting the height and length of the bars. The bigger woom ORIGINAL bikes are designed to last your child a really long time, ensuring that they're always able to find the optimal riding position as they get taller.

Our mission

We exist to encourage kids to love riding their bikes and make the world a little bit better along the way. For a child to fall in love with bikes, they not only need a bike that they've got total control over, but one that inspires confidence and makes them feel safe. If they are given a bike that they're expected to 'grow into', there's a risk that these important factors will be missing.

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