This guide will show you how to choose the right bike size using bike size charts and other methods. It covers the most popular bike types (hybrid, mountain, and road bikes).
You can use an interactive calculator that recommends a bike size based on your inseam length and bike type. Alternatively, you can choose the bike size based on one of the three methods explained below.
These methods will help you choose the correct bike frame size, ensuring that it fits, so you avoid riding discomfort, injuries, or returning your brand-new bike because it’s the wrong size.
Be sure also to check out the FAQ section, where you’ll find the answer to common questions like:
- What frame size do I need if I’m in-between sizes?
- Why is the correct bike size important?
- What to do if your bike is the wrong size?
Let’s dive in!
- Bike Size Calculator
- What Bike Size Do I Need?
- Method #1: Bike Size Based on Your Height (The Easiest Method)
- Method #2: Bike Size Based on Your Inseam Length and Bike Size Chart
- Method #3: Calculating the Bike Size
- How to Measure the Inseam Length?
- Choosing a Bike Size FAQ
Bike Size Calculator
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and City Bikes ROAD
and CX Bikes
DISCLAIMER: Please remember that the calculator does not consider your height, which may affect your bike size.
What Bike Size Do I Need?
To determine which bike size you need, use one of the following methods, sorted from the simplest to the most complex. Remember that simpler methods are less precise, while more complex methods offer greater accuracy.
Method #1: Bike Size Based on Your Height (The Easiest Method)
This is the easiest and quickest method to select a bike size. All you have to do is compare your height with the general bike sizing chart below.
|Your Height||Bike Size|
|4’11” – 5’3″||125 – 162||13 – 15||33 – 38|
|5’3″ – 5’7″||162 – 174||15 – 16||38 – 41|
|5’7″ – 5’11”||174 – 183||16 – 17||41 – 43|
|6’0″ – 6’2″||183 – 189||17 – 19||43 – 48|
|6’2″ – 6’4″||189 – 195||19 – 21||48 – 53|
However, this method doesn’t consider the type of bike, so it may not be as accurate as the methods below. As a result, the bicycle may not 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 most people. It is based on measuring your inseam length at home and comparing it with a bike size chart.
IMPORTANT NOTE: The inseam length for choosing a bike size is measured differently from that used for buying pants. Learn more
Once you measure the inseam length, use it to select the bike size. Most bicycle manufacturers use seat tube length in their bike size charts, along with other details, including the standover height.
The standover height is the distance from the ground to the top of the top tube.
If your inseam length is shorter than the standover height, the bike is too big for you.
The clearance, which is the difference between your inseam length and the standover height, should be around 1 to 2 inches.
This clearance is essential to prevent injuries caused by sudden or emergency stops.
Hybrid Bike Size Chart
Depending on the manufacturer, hybrid bikes usually come in descriptive sizes (XS-XL) and heights. However, you may still encounter all three types of size designations – in, cm, and descriptive sizes.
|Your Height||Your Inseam||Hybrid Bike Size|
Data source: Trek
And here is a helpful infographic:
Mountain Bike Size Chart
Generally, smaller mountain bikes usually come with 27.5″ wheels, while larger ones have 29″ wheels.
|Your Height||Your Inseam||Mountain Bike Size|
Data source: Trek
And here are the sizes in the picture:
Road Bike Size Chart
When choosing the size of your road bike, you should take extra care. Road cycling is a discipline where you spend long hours in the saddle, so selecting the right bike size is crucial.
It’s also essential to choose the right type of geometry. For instance, endurance geometry road bikes (where you sit more upright) are suitable for beginners, while aggressive (sporty/performance) geometry requires a certain amount of flexibility.
The following road bike size chart also applies to cyclocross and gravel bikes.
|Your Height||Your Inseam||Road Bike Size|
Data source: Trek
And again, an infographic:
Method #3: Calculating the Bike Size
As we know from Method #2, bike size is determined by the length of the seat tube. To effectively use this method, you will 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 to buy.
To calculate the size of your next bike, use the following formulas depending on the type of bike you want to buy. (Source)
- 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
After you receive the result, round it up to the nearest whole number. This will match the bike size charts above with a slight 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, your new road bike size should be 47 cm.
How to Measure the Inseam Length?
To measure your inseam length, follow these five simple steps or watch the video below:
- Prepare a 0.75 to 1-inch (1.9-2.5cm) thick book and a tape measure.
- Take off your shoes and stand with your back to the wall.
- 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 on one side.
- Measure the length from the top of the book to the floor.
- Take the measurement.
NOTE: The inseam for choosing the right bike size is different (a few inches longer) from the inseam used to choose the pants’ size. Remember that inaccurate inseam length may affect the recommended bike size.
Once you measure your inseam length (and eventually also your height), you can compare it with the bike size chart of the specific bike type. Based on it, you can choose the correct size.
Choosing a Bike Size FAQ
Choosing the correct bike size is easy when you know how to do it. You can use the bike size calculator that recommends a size based on your inseam length and bike type, or try one of the three methods I explain:
- The first method is simple but not very accurate. You only need to know your height and compare it with the universal bike size chart.
- The second method is the most accurate. First, measure your inseam length and decide what type of bike you want. Then, compare your inseam length with the hybrid, MTB, or road bike size chart, and you’ll have the right size to buy.
- The third method requires some math but is more accurate than the first. You need to know your inseam length and use special formulas to calculate the size of your next hybrid, mountain, or road bike.
If you’re still unsure about what size bike to choose, please ask in the comments below or email me.