We’ve compiled an extensive guide to bike sizing that makes figuring out the right size a whole lot easier. Below you’ll find great info on how different bikes are sized and how to find the best fit for men, women, and kids. Consulting a bike shop is always the best way to get the best fit, but this article will help you get a good idea of where you sit.

How do you figure out your bike size?

Bike sizing can be a bit of a pain sometimes because there isn't always one universal system of measurement that’s the same for all types of bikes and all riders.

Depending on whether you’re looking for an adult bike, a kid’s bike, a road bike, or a mountain bike, you’ll need to find out what your frame size or wheel size is.

We always recommend heading into your local bike shop to get the best possible fit, but you can also you the size charts and information in this guide to find the size that's best for you.

Adult bike sizing vs kid bike sizing

In a nutshell, adult bikes are sized by the frame, and kids bikes are sized by the wheel.

That means that there are two completely different measurement systems between adult and kids bikes. As children grow they’ll obviously start to fit on small adult bikes, but generally, kids 12 and younger will fit on bikes that are measured by the size of the wheels.

Women’s bike sizing

While some companies offer women-specific models with designs that aim to incorporate better-fitting components, there is no substantial difference between men’s and women’s bike sizes. Both women and men can use the same adult bike size charts below to find a great fit.

Road bike sizing vs mountain bike sizing

To make matters a little more confusing, sizing can also vary between styles of bike or the company that makes them. For example, road bikes and mountain bikes will often use different numbers to designate sizes.

Without going into too much detail, bike size used to be determined by measuring specific parts of the bike, like the seat tube. However, over time manufacturers have decided to update their measurement system since bike geometries have changed considerably. The goal was actually to make it easier for people, but since some companies still stick with the old systems, it can be a bit puzzling.

Important Info About Bike Size Charts

In the sections below we have broken down a few size charts for road bikes, mountain bikes, hybrid bikes, and kids bikes. It’s important to note that there is no single bike size chart that is universal to all brands or styles. Many bike manufacturers differ slightly in their sizing, but the charts below will give you a good idea of where to start.

Road Bike Size Chart

Road bikes will often use measurements in centimeters to denote frame sizes. If you’re looking at a road bike and you don’t know what size it is, start by measuring the seat tube, as that will give you a good ballpark idea.

When to size up or down on a road bike

Are you in between road bike sizes on our chart and unsure which way to go? Here are some points to consider:

Size up on a road bike if:

· you have long arms (your wingspan is larger than your height)

Size down on a road bike if:

· if you're mostly concerned with having a bike that's lighter and stiffer (sprinters)

· if you prefer an upright riding position

Mountain Bike Size Chart

Mountain bikes will either be measured in inches or, more likely, in a consumer-friendly Small/Medium/Large hierarchy. Newer mountain bikes can be tough to size without the help of a sticker or stamp on the frame, as geometries have changed so much in recent years that measuring tubes won’t typically give you very good insights.

Mountain bike wheel size for height

When choosing the wheel size for your next mountain bike, you'll want to take your height and your preferred riding style into account. It's true that smaller riders often feel more in control on smaller wheels, but depending on your level of experience and the desired ride characteristics, that may or may not be the best way to go for your specific goals. 

If you're a beginner, go with the first option on the suggested wheel size portion of the above chart. If you're an advanced rider, you might consider the other listed option and decide which wheel size will suit your riding style best.

As a rule of thumb, larger wheels have faster top speeds and roll over obstacles easier, while smaller wheels are more maneuverable and "playful". If your trail priorities are speed and efficiency, go with a larger wheel size. If your priorities are agility and playfulness, you might really enjoy a smaller wheel size.

We recommends riders go with the largest wheel size they can comfortable handle. We'd add to that by saying the best way to get a feel for what's comfortable for you is to come test ride a bike!

When to size up or down on a mountain bike

Are you in between mountain bike sizes on our chart and unsure which way to go? Here are some points to consider:

Size up on a mountain bike if:

· you're a more aggressive rider who appreciates a longer reach

· you prefer stability on descents to maneuverability

· you like to ride over and through obstacles rather than around them

· your wing span is greater than your height

· you are flexible and better at maneuvering your body to adjust to terrain

Size down on a mountain bike if:

· you prefer to ride more upright

· you riding style is more conservative than aggressive

· you prefer maneuverability over monster truck-like plowing power

· you are less flexible and tend to ride in a similar position

Other mountain bike size naming conventions

It's important to point out again that not all manufacturers use the same frame size naming conventions. Some brands prefer to "simplify" their sizing to numbers from 1 - 6 (instead of XS - XL) for example. The thing to keep in mind is that not all brands are sized the same, and it's important to look at the size charts provided by the brand you're looking at, as well as the bike's geometry chart, in order to get the best fit.

Why mountain bike sizing varies across brands & generations

In the early days of mountain biking, we used to size MTBs by the lengths of their seat tubes, as that would give someone a pretty good idea of what the standover height for a bike would be. That worked for a while, when frame design was relatively straightforward with top tubes and geometry that were more similar to road bikes.

As mountain bike design evolved, manufacturers were able to find more capable performance with different tube lengths and angles. With longer, more sloped top tubes and dropper post-ready designs (and more variations across brands), the seat tube is no longer the best way to approximate a bike's size. This paved the way for brands to start their own sizing methods.

Hybrid Bike Size Chart

Hybrid bikes like commuters and fitness bikes are great all-arounders that are extremely versatile and often very affordable. Most hybrid bikes use a Small/Medium/Large measurement system, but you might find a few companies who still use inches as the size denotation.

What to do if you're in between hybrid bike sizes

Go with the larger size if:

· you have long arms (an arm span that's longer than your height) or long legs

· the larger size has larger wheels and you prefer larger wheels

Go with the smaller size if:

· you have a longer torso but an average or shorter arm span/inseam

· you have bad hips or a bad back or other mobility issues

Kids Bike Size Chart

As we stated above, kids bikes are measured by the size of their wheels, and it’s much more straightforward than adult sizing. A 12-inch bike has 12-inch wheels, a 16-inch bike has 16-inch wheels, and so on. Here is a great general kids bike size chart to get started, but it’s always best to have your child try a bike before you buy it.

What to do if your child is in between kids bike sizes

Go for the larger size if:

· they feel confident on the bigger size

· they're getting into racing or biking as a sport

Go for the smaller size if:

· they're less confident riders

It's almost always better to size up with kids bikes, but only if they can actually handle the larger size. Kids grow up fast, and as a parent you'll want to try to give them a bike that they can ride for at least a few years, not just one.

There are some exceptions, though. Go too big and they may not be able to control the bike, which is more dangerous and certainly less fun. Kids will become better riders when they're riding a bike they feel confident on.