Bike Sizing Guide: What You Need to Know (Adults & Kids)

Family of 4 loading mountain bikes onto a pick-up truck

For many of us, learning to ride a bike is one of our fondest childhood memories. The sense of freedom and independence bike riding gives you is truly unique and it's something that often doesn't go away with age. That's why cycling is such a great way to have fun while you exercise. It's also super accessible and the perfect way to enjoy being active and outdoors with your friends and family. But to get the most out of the experience, it's important to have a bike that's the right size for you as riding a bike that's too big or small will impact your comfort, performance and ultimately your enjoyment of the bike. Whether you're planning to buy a bike online or in-store, it's a good idea to read a guide on bike sizes to get an understanding of how to size it correctly before you make a purchase. Let's take a look at how to find the right bike when it comes to adult and kid's bike sizes.

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Bike Sizes FAQs

What size bicycle is right for my height?

The right bicycle size depends on your height. For riders 5'0" to 5'3", a 15-16 inch frame suits best. Heights of 5'3" to 5'7" match well with 17-18 inch frames. 19-20 inch frames fit 5'8" to 5'11" riders, while 6'0" and above riders benefit from 21 inches or more. Proper sizing ensures comfort, control and efficient bike riding posture.

How do you tell if a bike is too big or too small?

A bike is too big if you struggle to straddle the top tube with feet flat on the ground, or if the handlebars feel out of reach. Signs of a bike being too small include cramped leg extension when pedalling and feeling hunched over the handlebars. Proper fit ensures a slight bend in the knee when the pedal is at its lowest point, allowing for efficient and comfortable riding.

Does height matter when buying a bike?

Yes, height matters significantly when buying a bike. A proper fit ensures comfort, control, and efficiency. Different frame sizes cater to various height ranges. Riders under 5'3" typically need smaller frames, while those over 6'0" require larger ones. Correct sizing ensures the right reach to handlebars, proper leg extension for pedalling efficiency and the ability to straddle the bike comfortably for safety.

Should your feet touch the ground on a bike?

When seated on a bike, it's ideal for your feet to touch the ground, or at least have the balls of your feet touch with a slight bending of the knees. This ensures stability when stopping. However, some advanced cyclists may prefer a slight tip-toe stance for better pedalling efficiency. Choose a bike size where you can comfortably reach the ground for safe starts and stops.

What happens if your bike is too big?

Riding a bike that's too big can lead to discomfort and reduced control. You might struggle to reach the handlebars, causing shoulder and back strain. Pedalling can be inefficient, as your legs may not fully extend, leading to fatigue. Balancing and stopping can also become challenging, increasing the risk of accidents. Proper bike sizes ensure comfort, safety and efficient riding.

What happens if you ride a bike that is too small?

Riding a bike that is too small can lead to discomfort and potential injuries. Your knees might hit the handlebars, causing pain and limiting your pedalling power. A cramped posture can lead to back and neck strain. Additionally, a small bike may not provide enough leg extension, reducing pedalling efficiency and overall speed. It's crucial to ride a properly sized bike for comfort and safety.

What Kind Of Bike Is Best?

Bike sizes vary a whole lot between different kinds of bikes and for this reason, the first step in working out the right size for you or your kids is choosing the best kind of bike for you. To work out what kind of bike you're looking for, there are a few things you should consider. For a start, where will you be riding the bike? Just around the city or do you plan on some mountain biking adventures? Also have a think about how often you'll be using it, how far you plan on going and what you'll use it for (casual commutes or workouts etc). Consider your riding terrain (road, trail or hybrid?). Frame material, such as aluminium for lightness or steel for durability, will impact how it will feel to ride the bike. Also factor in your riding style such as casual cruising or intense racing. Lastly, ensure proper bike size based on your height for comfort, control and efficient pedalling.

Man and woman riding Fluid Mountain Bikes on a trail

Why Your Height Is Important

Once you've worked out what kind of bike you're looking for, you'll need to work out which of the bike sizes is best for you. For both adults and kid's bike sizes, using your height is arguably the easiest way to find the right size bike (other than getting a professional bike fitting). Height is pivotal in selecting the right bike and defining comfort and performance. Having the correct frame size ensures a balanced stance, promoting efficient pedalling mechanics. For instance, a tall rider on a small frame risks discomfort and compromised control, whereas a short rider on a large frame may struggle with handling and stability. Optimal height alignment guarantees proper leg extension for power and safety, creating a harmonious ride between the rider and their bike. Kids' bikes are often also sized by age but, considering how much kids of the same age can vary in size, height will usually give you a better fit for an individual child.

Woman inspecting the seating of a Fluid Mountain Bike

Bike Sizing Charts

Use these charts to work out which size bike will fit you (or your kids) best. Just bear in mind, these should be used as a guide only as sizing can vary between models and manufacturers.

Kids' Bike Size Chart

Bike Size


Wheel Size

Kids Balance Bike (30cm)

Up to 100cm

12" (30cm)

Kids 12" (30cm)

80 - 100cm

12" (30cm)

Kids 16" (40cm)

100 - 120cm

16" (40cm)

Youth 20" (50cm)

120 - 135cm

20" (50cm)

Youth 24" (60cm)

130 - 145cm

24" (60cm)

Adults' Bike Sizing Chart

Bike Size


Frame Size

Youth X Small

145 - 160cm


Women's Small/Medium

150 - 172cm


Women's Medium/Large

162 - 182cm


Men's Small

160 - 167cm


Men's Medium

167 - 177cm


Men's Large

177 - 185cm


Men's X Large

185 -193cm


Further Adjustments

Fluid Mountain Bikes & helmets leaning against a raised wooden garden ledge

Once you've established the right size bike for you, there are a host of small adjustments you can make to tailor the bike to fit your unique body shape. Here are some of the main parts you can adjust on your bike to get the perfect fit for you.


Both the position of the saddle and the saddle itself have a huge impact of the fit and comfort of your ride. If you find the saddle uncomfortable to sit in, it may just be a matter of it not being suited to your body. There are many aftermarket bike saddles available for all body types, so it may just be a case of finding the right one for you. The saddle position can be adjusted by height, tilt (the angle of the saddle) and fore and aft position (moving it forwards or backwards). The height is adjusted by moving the seat pole up or down, while the tilt and fore and aft position can be adjusted directly under the saddle.


The position of the handlebars affects how far you have to reach as well as how upright your back will be when you ride. Stem height (how high/low your handlebars sit on the steer tube) can be adjusted by using an Allen key to take the handlebars off the steer tube and adding/removing the spacing rings that dictate how high the handlebars sit. Generally, the lower the handlebars, the flatter your back: the higher the handlebars, the more upright you will be. If you're not completely confident doing this yourself, always get a professional to make the adjustments for you.


Adjusting the cleats on your bike is great for creating a more personalised and comfortable fit. The cleats, which are fixed to cycling shoes and connect to the pedals, dictate foot position. Properly adjusted cleats align feet optimally over pedals, enhancing power transfer and efficiency. This reduces the risk of knee strain and hot spots on long rides. Cleat adjustments also fine-tune foot alignment, crucial for avoiding injury and maximising pedalling biomechanics. A precise fit ensures a stable and secure connection between foot and pedal, translating into improved control, especially during intense efforts or technical manoeuvres. It's an essential step for any serious cyclist seeking peak performance and comfort.

Crank Length

Adjusting the crank length on a bike can greatly enhance comfort and efficiency. Crank length, which is the arm connecting the pedals to the bike's drivetrain, impacts leg extension and pedal stroke. The correct crank length ensures optimal knee and hip alignment, reducing the risk of strain and injury. Riders with longer legs may benefit from longer cranks for better leverage, while shorter cranks can benefit those with shorter legs for smoother pedalling. Fine-tuning the crank length also improves pedalling efficiency, translating more power to the wheels. This customisation maximises performance and comfort, making it a worthwhile adjustment for cyclists aiming for a precise and tailored fit.

Find The Best Bike Size For You At Anaconda Today

Fluid Mountain Bikes & helmets parked on grass by a beach

A bike will not only help you keep fit and active, but it will also bring you a whole lot of enjoyment too. It's also a long-term purchase so it's worth spending the time to get the right size and fit to make sure your ride is as comfortable as it should be. Anaconda has a huge range of bikes as well as a bike workshop for all your fitting and maintenance needs. Make sure you check out our Adventure Centre for more helpful tips and exciting destinations that you can visit with your friends, loved ones and family. If you liked our Bike Sizing Guide, then you might also like some of our other articles for awesome destinations and tips such as:

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