The perfectly sized bike can make or break your ride, no matter what kind of cyclist you are. Not only is an appropriately sized bike important for performance, it’s also important for comfort and safety. From road cycling to riding mountain paths, you need a bike that fits you like a glove — and here’s how to do it.
What’s in this article?
- How are bikes measured?
- How to measure your height for a bike
- Tips on how to try out a bicycle
- More cycling resources
Quick bicycle size charts
Make the most of your bicycle by making sure it’s the right size.
Most bicycles are measured by the size of the frame — more specifically, the size of the seat tube.
The bicycle’s seat tube
The seat tube is the part of your frame that extends from the cranks (or pedals) to the padded seat. It’s highlighted in red below.
More specifically, manufacturers may measure the bicycle frame from the bottom bracket which attaches the cranks to either the:
- Top of the bike seat tube: Where the tube meets the seat saddle
- Center of the bike seat tube: Where the seat tube meets the top tube
Below you can find the top tube highlighted in green, the bottom bracket in blue, and the seat tube in red.
Some manufacturers measure this in inches, while others measure in centimeters. This will likely depend on where your bicycle is from (i.e. Europe, the United States, etc.) or what type of bicycle it is.
For example, road bikes are more often measured in centimeters. However, mountain bikes are more likely to be measured in inches.
To get this measurement on your own you’ll need:
- A measuring tape
- To know exactly where the bottom brackets are on your bicycle
- To know exactly where your bicycle’s seat tube is
- How your bike’s manufacturer determines seat tube length (i.e. to the center or the top of the seat tube)
The bicycle’s reach vs. stack measurements
If you want to compare bicycle sizes, seat tube measurements may be difficult to get consistent — especially if you shop online.
One manufacturer may choose to define seat tube length from the bottom bracket to the top of the seat tube, while another measures to the center of the seat tube. With two different measurement styles, comparing models is tricky at best.
This is why some bicycle manufacturers have moved towards calculating reach and stack. These measurements give cyclists a more uniform way of comparing bike sizes.
What is bicycle reach?
In bicycle geometry, bike reach is the horizontal distance from the center of the top of the head tube to the bottom bracket.
What is bicycle stack?
Bike stack measures the vertical distance from the center of the top of the head tube to the bottom bracket.
Bike stack and reach are usually measured in either centimeters or millimeters. To get this measurement on your own, you’ll likely need:
- A plumb bob if you plan to measure without tracing
- A measuring tape if you plan to trace measurements
A plumb bob is a string with a weight on the end of it that lets you measure vertical distance. This will help you get an accurate stack measurement.
Alternatively, you can mark ticks on a surface behind your bicycle (make sure it’s standing up straight), and measure the distance between those ticks with a measuring tape.
How to measure your height for a bike
Now that you know how bicycles are measured, let’s explore how to measure your own height. Once you have an accurate height measurement, you’ll have a better chance at choosing the best bike frame for your size. There are two primary ways to do this.
How to measure height and inseam for a bicycle
You’ll need a measuring tape and maybe a friend to help you out. First, measure your height from tip to toe. You can do this by using tick marks on a wall and measuring after, or having a friend use a measuring tape against you.
Second, measure your inseam — or the inside of your leg from the groin to the ground. Stand roughly shoulder-width apart to get this measurement. You can have a friend measure you or use the tick mark method.
Pro tip: Measure your height and inseam with, and without, your riding shoes. Having both measurements will come in handy when you’re ready to shop.
Measure each one in inches and centimeters. This will come in handy if you shop online for a bicycle since some manufacturers measure this differently. If you can’t measure in both inches and centimeters, measure in whichever one you can and then use an online calculator to find the other.
How to measure stand over height for a bike
An easier way of measuring yourself is to figure out the ideal stand over height of a bicycle.
A bicycle’s stand over height measures from the ground to the top of the top tube. Theoretically, the stand over height of a bicycle should give you about 2 – 2.5cm (or about 1in) of clearance between your groin and the top tube.
When you stand and straddle your bicycle, your groin shouldn’t be touching the top tube. This clearance gives you space for comfort, and prevents injury when you jump on and off the seat saddle.
To calculate the stand over height, measure your inseam and fold in about an inch of clearance on top of that.
Tips on how to try out a bicycle
Whether you want to shop online, at a local bike shop, or at a major bicycle retailer, it might be a good idea to “try on” a bicycle before you buy it. This is easier to do in person because online retailers may have a strict return policy — and even if they don’t, shipping a bicycle can be a challenge and expensive.
Use these tips to have a more productive experience when you’re ready to buy a bicycle. Remember that not all retailers are the same, and your experience may vary from store to store.
- Have your height and inseam measurements handy
- Be ready to discuss bicycle measurements in inches or centimeters
- Take a look at a bicycle size chart beforehand
- Bring your cycling shoes to wear when you test drive a bicycle
- Make sure the stand over height has enough clearance for safety and comfort reasons
- “Try on” your exact size, and a size above and below, to find the right fit
- Ask about return and exchange policies before purchasing the bicycle
Bicycle size charts
If you already know your measurements, use the charts below to find the right bike size for you. Keep in mind that manufacturers may measure models differently. These charts are meant to be a general guide to help you get started.
BMX bike size chart
| Rider Height & Info | Suggested BMX Bike Size | |
|---|---|---|
|
Feet/Inches |
Centimeters |
Bicycle Wheel Size |
|
3'7" - 4'0" |
110cm - 122cm
|
16" |
|
4'0" - 4'10" |
122cm - 147cm |
18" |
|
4'10" - 6'4" |
147cm - 193cm |
20" |
Electric bike size chart
| Rider Height & Info | Suggested Electric Bike Frame Size | |
|---|---|---|
|
Feet/Inches |
Centimeters |
Frame Size |
|
4'10" - 5'2" |
148cm - 158cm
|
33 - 37 |
|
5'2" - 5'6" |
158cm - 168cm |
38 - 42 |
|
5'6" - 5' 10" |
168cm - 178cm |
43 - 47 |
|
5'10" - 6'1" |
178cm - 185cm |
48 - 52 |
|
6'1" - 6'4" |
185cm - 193cm |
53 - 57 |
|
6'4" - 6'6" |
193cm - 198cm |
58 - 61 |
Mountain bike size chart
| Rider Height & Info | Suggested Mountain Bike Frame Size | |
|---|---|---|
|
Feet/Inches |
Centimeters |
Frame Size |
|
4'10" - 5'2" |
148cm - 158cm
|
XS |
|
5'3" - 5'6" |
159cm - 168cm |
S |
|
5'7" - 5' 10" |
169cm - 178cm |
M |
|
5'11" - 6'1" |
179cm - 185cm |
L |
|
6'2" - 6'4" |
186cm - 193cm |
XL |
|
6'5"+ |
193+ |
XXL |
Road bike size chart
| Rider Height & Info | Suggested Road Bike Frame Size | |
|---|---|---|
|
Feet/Inches |
Centimeters |
Frame Size |
|
4'10" - 5'0"
|
148cm - 152cm
|
XX-Small (47cm - 48cm)
|
|
5'0" - 5'3"
|
152cm - 160cm
|
X-Small (49cm - 50cm)
|
|
5'3" - 5'6"
|
160cm - 168cm
|
Small (51cm - 53cm)
|
|
5'6" - 5'9"
|
168cm - 175cm
|
Medium (54cm - 55cm)
|
|
5'9" - 6'0"
|
175cm - 183cm
|
Large (56cm - 58cm)
|
|
6'0" - 6'3"
|
183cm - 191cm
|
X-Large (58cm - 60cm)
|
|
6'3" - 6'6" |
191cm - 198cm
|
XX-Large (61cm - 63cm)
|