What Size Bike Do I Need – Bike Size Charts for Adults and Kids

What Size Bike Do I Need

What Size Bike Do I Need?

Many people find themselves faced with this question at some point.

What size bike do I need? Finding the right size bike for you will help narrow down your search if you’re in the market for a bike.

Just like people, bicycles come in various forms and sizes.

The best one for you is based on your body type, cycling needs, and personal preferences.

A good-fitting bike is comfortable and enjoyable to ride.

In this article, we’ll guide you on how to choose a bike that’s the right size for you, so stick around.

How Do You Determine Your Bike Size?

bikes lined up in a bicycle shop

It’s not much fun to ride a bike that doesn’t fit you well.

Figuring out the right size bike for you is an important first step before you start shopping.

It takes more than having the right frame size to find a good fit.

Your bike should be comfortable at all major contact points.

Such as the saddle, handlebars, and pedals.

Take some time to learn about the important factors to help you select the perfect bike for your needs.

Factors like frame geometry affect the fit and handling of your bike.

The size, shape, and components all play a role in how it will perform.

If buying a bike in a store, the obvious option is to try it out first.

This will help you evaluate the bike’s handling and make sure you’re comfortable with it.

If buying in-store, you may have a professional bike fit measurement.

This will ensure the bike size matches your dimensions.

Bicycle Frame

bicycle frames displayed on a wall

Picking the right bike frame size is essential for your comfort.

Proper frame size also decreases the chance of injury and body strain.

Many cyclists aren’t aware of how important proper size frame is until it’s too late.

A bicycle’s frame is its most important component.

The frame connects all the bike’s parts and is made of one piece. The frame is tubular (hollow) rather than solid metal.

Top tube length is the most important factor when it comes to deciding the right frame.

The top tube length measures the horizontal distance between the head tube and the seat tube.

It is important to get the right top tube length because it affects how comfortable you are when riding, as well as how efficient your pedaling is.

A longer top tube will provide more stability while a shorter one will give you more agility while riding.

The best way to determine what size frame you need is to measure your torso and arm length, then use a sizing chart to find the right frame size for your body type.

The length of the seat tube is often used to gauge proper size, but it’s not the main factor.

The most important factor is the rider’s height, inseam length, and flexibility.

The seat tube length should be chosen based on the rider’s body measurements and riding style.

A longer seat tube will provide more stability for a taller rider, while a shorter seat tube will be better for a shorter rider who wants to have more maneuverability.

bicycle mechanic aligning rear bike wheel

How to Measure the Bike Frame Size

Manufacturers don’t all measure frame size the same way.

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So you’ll need to compare apples to apples by looking at a few basic metrics.

  1. Find the seat tube’s top (this is what holds the seat post in place)
  2. Find the center of the bottom bracket (this holds the crank arms together)
  3. Take a measurement between these two places
  4. Take note of the measurement in both cm and inches
  5. This is the Bike Frame Size

Bike Frame Geometry

Bike Frame Geometry

Bike Frame Geometry is one of the most important factors to consider when choosing a bike.

The geometry of your frame affects the handling and fit of your bike.

Different bikes have different geometries, so it’s important to choose a bike that will fit you well.

The geometry of your frame also affects the way your bike rides.

A bike with a slacker headtube angle will be more stable at high speeds, while a bike with a steeper headtube angle will be more agile.

The size of your frame is also an important factor to consider.

Bike frames are measured in inches or centimeters.

The size of your frame should be based on your height and weight.

If you are between sizes, it’s usually better to go with the larger size.

Riding Style

Some bikes are made for riders who want a more aggressive racing position.

Others allow riders to cycle much more casually, in an upright position.

Racing-oriented cyclists tend to choose bikes with longer top tubes.

These have more of a drop between the seat and the handlebar.

More casual riders prefer bikes with shorter top tubes and less of a drop to the handlebar.

Type Of Bike

man comparing bikes in a bicycle shop

The size of the bike you buy will be determined by the sort of bike you choose.

The sort or style of riding you undertake will also affect the size you require.

The size of bike you buy will be determined by the sort of bike you choose.

The sort or style of riding you undertake will also affect the size you require.

For example, if you are planning to use your bike for commuting, then a road bike or a hybrid bike would be a good choice.

These bikes are generally lighter and easier to maneuver in traffic.

If you are looking for a bike to take on trails or off-road riding, then a mountain bike would be a better option.

Mountain bikes tend to be larger and heavier, with wider tires to provide more stability and traction on rough terrain.

Ideally, you would want to test different types of bikes to see what feels most comfortable before making a purchase.

There’s no such thing as the “correct” or “wrong” size; it all depends on personal preference and what feels comfortable.

Check out my post What Is The Largest Size Mountain Bike For Men if you’re curious about the largest sized bikes.

Bike Fit

Bike fit is a very important aspect of cycling and many bike shops will offer a professional fitting service.

When looking for a new bike, you need to ask yourself some questions:

  • How often will you be riding the bike?
  • How far do you plan on riding? (Short Commutes / Long rides / Racing) 
  • How much are you willing to spend? ($200 – $2,000)
  • What type of riding are you planning to do? (Mountain, Road, Gravel, Cyclocross etc.)
  • What features are important to you? (Suspension, frame material, gearing, brakes etc.)
  • Do you need any special accessories? (Helmet, lights, racks etc.)
  • Are there any specific brands or models that you are interested in? (Specialized, Cannondale, Trek, etc.)

How Do You Determine Your Bike Size?

Selecting a bike size is determined by the type of bike, your inseam height, riding style, frame measurement, and geometries.

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1. Type of Bike: Different types of bikes come in different sizes. Mountain bikes, for example, usually have larger frames than road bikes.

2. Inseam Height: Your inseam height is the distance from your crotch to the floor. Knowing your inseam height will help you determine what size frame you need for the bike.

3. Riding Style: If you plan on riding aggressively or doing stunts, you may want a larger frame size than if you plan on leisurely rides around town.

4. Frame Measurement: The frame measurement is the length of the seat tube from the center of the bottom bracket to the top of the seat tube collar. This measurement will help you determine which size bike is best for your body type and riding style.

5. Frame Geometries: Bike frame geometries refer to how a bike’s frame is designed and built, including angles and lengths of tubes, as well as other components like handlebars and cranksets that affect fit and performance. Knowing your geometries can help you select a bike that fits your body type and riding style perfectly.

Bike Size Charts

The Bike Size Charts below can help you determine the appropriate bike size.

At the end of the day, you’ll have to try on a few sizes to figure out what fits best.

I’ll break the chart down by type.

It’s very helpful to know all the parts of your bike, so check check out my other post for more info.

Rider’s Height & Bicycle Size

Height (ft/in)Height (cm)Leg inseam (inches)Leg inseam (cm)Suggested Frame Size (in)Suggested Wheel Size
4′ 10 – 5′ 3″147-160cm25 – 28″62-70 cm13 – 14″26″
5′ 4 “- 5′ 7”160 – 170cm25 – 30″63 – 76 cm15 – 16″26″
5′ 5″ – 5′ 9″165 – 175cm26 – 31″66 – 78 cm16 – 17″27.5″
5′ 9″ – 6′ 0″175 – 183cm27 – 32″68 – 81 cm17 – 18″27.5″
6′ 0″ – 6′ 3″183 – 190cm28 – 33″71 – 83 cm18 – 19″29″
6′ 1″ – 6′ 6″190 – 200cm29 – 34″73 – 86 cm19″ +29″

Mountain Bikes Size Chart

Rider heightLeg inseam                                               Suggested Frame Size
Feet/InchesCentimetersInchesCentimetersInchesSize
4`10”-5`1”148-158 cm24-29”61-73 cm< 14″XS
5`1″-5`5″158-168 cm25-30”63-76 cm15” / 16″S
5`5″-5`9″168-178 cm26-31”66-78 cm16” / 17″M
5`9″-6`0″178-185 cm27`-32`68-81 cm17″ / 18″L
6`0″-6`3″185-193 cm28`-33`71-83 cm18″ / 19″XL
6`1″-6`6″193-198 cm29`-34`73-86 cm19″ +XXL

Commuter Bicycle Size Chart

Rider heightLeg inseam                                               Suggested Frame Size
Feet/InchesCentimetersInchesCentimetersInchesSize
4`10”-5`1”148-158 cm24-29”61-73 cm< 14″XS
5`1″-5`5″158-168 cm25-30”63-76 cm15” / 16″S
5`5″-5`9″168-178 cm26-31”66-78 cm16” / 17″M
5`9″-6`0″178-185 cm27`-32`68-81 cm17″ / 18″L
6`0″-6`3″185-193 cm28`-33`71-83 cm18″ / 19″XL
6`1″-6`6″193-198 cm29`-34`73-86 cm19″ +XXL

Road Bicycle Size Chart

Rider heightSuggested frame size
Feet/InchesCentimetersCentimetersSize
4`10”-5`0”148-152 cm47-48 cmXXS
5`0″-5`3″152-160 cm49-50 cmXS
5`3″-5`6″160-168 cm51-52-53 cmS
5`6″-5`9″168-175 cm54-55 cmM
5`9″-6`0″175-183 cm56-57-58 cmL
6`0″-6`3″183-191 cm58-59-60 cmXL
6`3″-6`6″191-198 cm61-62-63 cmXXL

Bike Size Calculator

The Bike Size Calculator is one of the easiest and quickest ways to determine your ideal bike fit.

While there’s no substitute for a professional bike fit, this calculator will get you pretty close.

Check out this Bike Size Calculator for reference.

A good bike fit is pretty much the difference between discomfort and having a great time on your bike ride.

Trying on various sizes and options isn’t always possible.

There are many different sorts of bikes, including mountain bikes, road bikes, city bikes, exercise bikes, touring cycles, and urban bikes.

The appropriate frame size for the same person varies depending on their activities.

children on their bikes in the grass

What Size Bike Do I Need for My Child?

Bikes with the same wheel size can have wildly different overall sizes.

Consider the following tips to get your child the right-size bike:

1. Measure Your Child’s Inseam: The best way to determine the right size bike for your child is to measure their inseam (the distance from the ground to the top of their inner thigh). This measurement will give you an idea of what size frame they need.

2. Look For Adjustable Features: Many bikes come with adjustable features such as seat height and handlebar height, so you can customize it to fit your child’s size.

3. Test Ride Different-Sized Bikes: Have your child test ride several different-sized bikes before you buy it to make sure it fits them properly and that they feel comfortable on it.

4. Consider a Balance Bike: If your child is just starting out, consider getting them a balance bike instead of a traditional pedal bike. Balance bikes are designed for young children and help them learn how to balance on two wheels without having to worry about pedaling yet.

5. Ask For Help: If you’re still unsure about which size bike is best for your child, don’t hesitate to ask a salesperson or someone at a local bike shop for advice. They should be able to point you in the right direction!


Children’s Bicycle Size Chart

Wheel sizeAgeHeightInseam
12”2-32’10” – 3’4”14-17” 35-42 cm
14”3-43’1” – 3’7”16-20” 40-50 cm
16”4-53’7” – 4’0”18-22” 45-55 cm
18”5-63’9” – 4’3”20-24” 50-60 cm
20”5-84’0” – 4’5”22-25” 55-63 cm
24”7-114’5” – 4’9”24-28” 60-72 cm

The Wrap-Up!

Cycling is a fun & satisfying activity.

But if you’re riding a bike that doesn’t fit you, that joy will quickly turn into discomfort and fatigue.

Hopefully, with the aid of this guide, you’ll be able to pick the right size bike for your needs.

What’s Next?

If you enjoyed this article, go check out What Is Cadence In Cycling – How To Measure & Improve Yours!

Happy Cycling!

About Informed Cyclist
Michael Rogers
I’m Michael, a cycling fanatic and the founder of Informed Cyclist. I started this site to give back to the sport I love! My mission is to bring the very best cycling advice & know-how to my readers. I hope you enjoy this site as much as I love working on it. I put a lot of heart & effort into it!

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