Bike Size Guide: What size bike do I need?

Before diving into bike sizes, grab a measuring tape. Stand against a wall with your shoes off and measure from the floor to the top of your head. This number is your golden ticket to finding a bike that feels just right.

Not all bikes are built the same because not all rides are the same. The best bike for you depends entirely on where you’ll be riding.

Commuting or long road rides - A road bike is designed for smooth tarmac, speed, and efficiency. Lightweight frames, thin tyres, and drop handlebars help you go the distance with ease.

Exploring trails, forests, or rocky paths- A mountain bike is your best bet. With wide, grippy tyres and suspension to absorb the bumps, it’s built for adventure. See our mountain bike size guide for more details. 
 
A mix of both - Hybrid bikes combine features of road and mountain bikes, perfect for city streets, parks, and light trails.

Heading to the pump track or pulling off tricks - A BMX bike is small, sturdy, and built for jumps and stunts.

It’s important to choose your type of bike before picking the right size—geometry, tyre width, and frame design vary depending on the kind of riding you’ll be doing. Find the right fit, and you’ll enjoy every ride that much more.

Your ideal bike frame size depends on your height and inseam length (the distance from the floor to your inner thigh).

Most bike brands have size charts to help match you to the perfect frame—use them.

If you’re between sizes, consider your riding style: a smaller frame for better control, or a larger one for speed and stability.

Bike sizes are based on the seat tube length—the part of the frame running from the bottom bracket (where the pedals attach) to the top of the tube.

The exact measuring point varies by brand. Some measure to the top of the seat tube, others to the center of the top tube, but it’s all about that seat tube.

Mountain bikes usually use inches or Small/Medium/Large sizing.

Road bikes are typically measured in centimeters.

Hybrid bikes use either system.

As frame size increases, so does the bike’s overall length, so a larger bike means a longer reach.

For adults, frame size is the key to getting the right fit.

For kids bikes, it’s all about wheel size: the bigger the wheel, the bigger the bike. Here’s a quick guide:

12” wheels: Ages 2-4
16” bikes: Ages 4-6
20” wheels: Ages 6-8
24" bikes: Ages 8-12
26” wheels & beyond: Pre-teens & up (time to check adult sizes).

When in doubt, let your child test-ride a few options to see what feels best. If you’re visiting a store, you’re free to ride around the store-floor

Most women’s bikes are designed with shorter top tubes for a more comfortable reach and narrower handlebars for better control.

But sizing works just like unisex bikes—height and inseam length determine the best fit. Many female riders also find unisex bikes fit just as well, especially with a few adjustments to the saddle and stem.