How to Choose the Right Bike Size? (3 Methods + Calculator)

Bike Size Chart - How to Choose Bike Size

In this guide, you are going to find out how to choose the right bike size. It covers hybrid, mountain, and road bikes so if you plan to buy a bike online, you are in the right place!

You can use an interactive calculator that will recommend you a bike size based on your inseam length and bike type. Or you can choose the bike size based on one of the 3 methods that I explain below.

All these tools will help you to choose the correct bike frame size so you avoid returning your brand new bike ordered online due to it being the wrong size.

Also, make sure you check the FAQ section, where you will find the answer to the most common questions like:

  • What frame size do I need if I’m in-between sizes?
  • Why is the correct bike size important?
  • Does your age influences the bike size you should get?

Let’s dive in!

Bike Size Calculator

Find the right bike frame size using this frame calculator.
Simply choose the bike type, input your inseam length and get the size recommendation. Learn how to correctly measure your inseam for choosing a bike size.

Choose the Bike Type
How to choose a bike?
mountain bike icon 250px newMTB
Cross-Country, Trail,
and Enduro Bikes
hybrid bike icon 250px newHYBRID
Trekking, Commuter,
and City Bikes
road bike icon 250px newROAD
Road, Gravel,
and CX Bikes
Enter Your Inseam Length
How to measure your inseam?

inch cm

Disclaimer: Please remember, the calculator does not take into account your height, which may affect the resulting bike size.

What Bike Size Do I Need?

The following methods are sorted from the simplest to the more complex. Simpler methods are less accurate than more sophisticated methods and vice versa.

If you don’t know what type of bike to choose yet, visit my article on How to Choose a Bike. It contains an interactive guide that will help you with your bike selection.

Method #1: Bike Size Based on Your Height (The Easiest Method)

This is the easiest method by which you can select the bike size. It’s the fastest method to find a bike size. All it takes is to compare your height with the general bike sizing chart below.

Your HeightBike Size
4’11” –  5’3″125 – 16213 – 1533 – 38
5’3″ –  5’7″162 – 17415 – 1638 – 41
5’7″ –  5’11”174 – 18316 – 1741 – 43
6’0″ –  6’2″183 – 18917 – 1943 – 48
6’2″ –  6’4″189 – 19519 – 2148 – 53

Unfortunately, this method does not take into account the type of bike. This means it is not as accurate as the methods below. So, there is a risk that the bicycle won’t fit you perfectly.

Method #2: Bike Size Based on Your Inseam Length and Bike Size Chart

This is probably the best bike sizing method for the vast majority of people. It is based on the inseam length that you can measure at home.

IMPORTANT NOTE: The inseam lenght for choosing a bike size is measured differently from an inseam length for buying pants. Learn more on how to measure it correctly.

Once you measure the inseam length, use it to select the bike size. Most bicycle manufacturers use the seat tube length in their bike size charts alongside many other details, including the standover height.

The standover height is the distance from the ground to the top of the top tube.

bike size - seat tube length and standover height
Seat tube length and standover height

If your inseam length is shorter than the standover height, the bike is too large for you.

The clearance, which is the difference between your inseam length and the standover height, should be roughly between 1 to 2 inches.

You should have some clearance to prevent injuries caused by accidental stopping on your bike.

Hybrid Bike Size Chart

Depending on the manufacturer, hybrid bikes use all 3 types of size designations – in, cm, and descriptive sizes (S, M, L…).

Hybrid bike size chart
Hybrid bike size chart | Data source:

Mountain Bike Size Chart

The size of mountain bikes is usually given in inches or descriptive sizes.

Mountain bike size chart
Mountain bike size chart | Data source:

Road Bike Size Chart

The size of road bikes is usually given in centimeters or descriptive sizes.

Road bike size chart
Road bike size chart | Data source:

This size chart is also applicable to cyclocross and gravel bikes.

Method #3: Calculating the Bike Size

As we know from Method #2, the bike size is measured based on the length of the seat tube. To successfully use this method, you will also need to know the length of your inseam (learn how to measure it correctly).

To calculate the size of your next bike, use the following formulas depending on the type of bike you want.

  • Inseam Length (cm) × 0.685 = Hybrid Bike Size (cm)
  • Inseam Length (cm) × 0.225 = MTB Bike Size (inches)
  • Inseam Length (cm) × 0.665 = Road Bike Size (cm)

1 in = 2.54 cm
1 cm = 0.39 in

Once you get the result, make sure you round it up to whole numbers. Then, the result will match the bike size charts above with a small deviation.

Example of Calculating the MTB Bike Size:

Your inseam length is 33 inches and you want to buy a new mountain bike. Let’s do the math:

Convert cm to inches: 33 inches × 2.54 = 83.8 cm
Calculate the bike size: 83.8 cm × 0.225 = 18.8 ≐ 19 inches

The size of your new mountain bike should be 19 inches.

Example of Calculating the Road Bike Size

Your inseam length is 70 cm and you want to buy a new road bike:

70 cm × 0.665 = 46.55 cm ≐ 47 cm

As you can see, the size of your new road bike should be 47 cm.

How to Measure the Inseam Length?

To measure your inseam length, follow these 5 simple steps or watch the video below:

  1. Prepare a 0.75 to 1-inch (1.9-2.5cm) thick book and a tape measure.
  2. Take off your shoes and stand with your back to the wall.
  3. Put the book in your inseam, firmly pull it up and hold it with your tights. Make sure the book is pressed against the wall with one side.
  4. Measure the length from the top of the book to the floor.
  5. Take the measurement.

NOTE: The inseam for choosing the right bike size is different (it is a few inches longer) from the inseam used to choose the pants’ size. So keep that in mind because inaccurate inseam length may affect the recommended bike size.

Before you proceed to the bike size charts, measure your inseam

Once you measure your inseam length (and eventually also your height), you will be able to compare it with the bike size chart of the specific bike type. Based on it, you can choose the correct size.

Bike Size FAQ


Choosing the right bike size is not difficult when you know how to do it. You can take advantage of the bike size calculator that recommends you a bike size based on your inseam and bike type.

Or, use one of the 3 methods I explained:

The first method is the simplest and the least accurate. The only thing you need to know is your height and compare it with the universal bike size chart.

The second method is the best method to accurately choose your bike size. You need to measure your inseam length and decide what type of bike you want to buy. Then, just compare your inseam length with the hybrid, MTB, or road bike size chart and that’s it. You can order your new bike online.

The third method requires you to do simple math. You also need to know your inseam length. Once you measure it, you can use special formulas to calculate the size of your next hybrid, mountain, or road bike.

If you are still not sure what size of the bike is right for you, feel free to ask in the comment section below or send me an email. I will gladly help you.

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