by Stan Purdum
Trying to figure out the correct bike size for yourself or maybe for a friend or for a kid’s bicycle? Here’s a chart to help you estimate which sized kids bike, road bike, hybrid bike or mountain bike you should probably ride.
The best way to figure out the right bicycle size is to try it out in person, at a local bike shop. But that isn’t always possible, and maybe you’re looking at a bike for sale on Ebay or somewhere else online.
A good bike shop can help you identify more than just if the frame size is correct. They can also help you figure out your optimal seat height and position, and whether or not the reach to the handlebars is optimal for comfort and bike control. Often, you can pay for a bike fitting at a good bike shop even if you didn’t buy the bicycle there, and it’s often worth the money to set up your bike fit optimally if you plan to spend more than an hour at a time riding the bike.
If you are actually spending money at a bike shop anyway, buying accessories like a helmet, tubes, a bike bag or apparel, it can be appropriate to ask for bike size guidance even if you don’t ultimately buy your bicycle at that shop. But to just go in to a bike shop and have someone help you figure out your bike size and to leave without ever intending to buy anything there is called “showrooming.” It is unfair to your local bike shop and wastes the time of paid employees.
Even experienced cyclists can find it hard to pick exactly the right size frame, because the geometry of a bicycle can vary depending on its design. The type of bike, your height and your riding style can also make a difference.
The most important body measurements for determining the correct bicycle frame size are your height and your inseam. While these two numbers alone will not guarantee that a bike is a perfect fit, by using them and a sizing chart, you can eliminate bikes that clearly are too tall or too short for you.
You no doubt already know your height, but the inseam measurement you need for bike sizing is not the same as the one you use when buying jeans, which will be at least two inches shorter than your actual inside leg length.
To find inseam length for cycle-fitting purposes, remove your shoes and any baggy trousers. Then stand with your feet about 8 inches apart and place a spirit level or other straight edge — even a book — in your crotch, pulling it up to the highest possible position, so that the pressure is similar to what you feel when sitting on a bike saddle. Keeping the straight edge parallel to the floor, measure the distance from the top of it to the floor. (It may be easier to have a helper do this.) For accuracy, repeat the measurement several times and calculate the average.
The inseam measurement will help you get a bike you can comfortably straddle, while the height measurement will help you get a one that will accommodate your upper body dimensions.
Next, using these charts below, determine which size bike will work for you.
Adult bicycle frames are normally measured from the middle of the bottom bracket to the top of the seat tube. Road bikes sizes are usually given in centimeters while mountain bike and hybrid sizes are usually given in inches. If you’re looking at a used bike online, you might need to contact the seller to provide this information, although they usually include it in the description. For hybrid sizing, see here.
Road Bike Size Chart
|Your Height / Inseam||Bike Size|
|5′ to 5’4″ under 27″ inseam||XS (extra small) 49 cm bike|
|5’4″ to 5’8″ with 27″ to 29″ inseam||S (small) 49 cm to 54 cm bike|
|5’8″ to 5’10” with 29″ to 31″ inseam||M (medium) 52 cm to 56 cm bike|
|5″10″ to 6′ with 31″ to 33″ inseam||L (large) 54 cm to 58 cm bike|
|6′ to 6’3″ with 33″ to 35″ inseam||XL (extra large) 56 cm to 61 cm bike|
|6’3″ to 6’6″ with 35″ and up inseam||XXL 61 cm bike or bigger|
We’ve charted road, mountain and kids bike sizes separately because each is measured differently because of their design and intended use. While there are several differences, hybrids, for example, are designed for more comfort than are road bikes, usually having a taller head tube and shorter top tube. Mountain bikes usually have a lower top tube than road bikes.
Mountain Bike Size Chart
|Your Height / Inseam||Bike Size|
|5′ to 5’3″ under 27″ inseam||XS (extra small) 13 inch bike|
|5’3″ to 5’7″ with 27″ to 29″ inseam||S (small) 15 inch bike|
|5’7″ to 5’11” with 29″ to 31″ inseam||M (medium) 17 inch bike|
|5’11” to 6’2″ with 31″ to 33″ inseam||L (large) 19 inch bike|
|6’2″ to 6’4″ with 33″ to 35″ inseam||XL (extra large) 21 inch bike|
|6’4″ to 6’6″ with 35″ and up inseam||XXL 23 inch or bigger|
Children’s bikes, as the chart shows, are sized according to the wheel size of the bike and the age of the child.
Kids’ Bike Size Chart
|2 to 3 years||12 inch|
|3 to 5 years||14 inch|
|5 to 7 years||16 inch|
|5 to 8 years||18 inch|
|7 to 9 years||20 inch|
|9 to 12 years||24 inch|
After you’ve narrowed your search by frame size, check to see whether the bike is for women or for men. While the two may look similar at a glance, those made specifically for women have geometry that better accommodates women’s usually shorter height and upper body dimensions. Thankfully, gone are the days when a “women’s” bike was a men’s bike painted pink.
For example, my adult daughter and I both have a similar inseam measurement, but she is 5’2″ and I am 5’7″. She can straddle my road bike, and it a pinch, ride it. But because her torso is shorter than mine, to do so very long forces her into an uncomfortable stretched out position. Her bike is from the extra small category while mine is from the medium category, but hers is also designed for a woman.
All of that said, the bike frame that works best for you is the one that fits your physiology. Thus, some women may be more comfortable on a “men’s” bike and vice versa. So if your body proportions fall outside of the norm, don’t assume you have to ride a bike that’s a poor fit. Any modern bike can be thought of as potentially “unisex.”
Once you have in your possession a bike that’s the correct frame size for you, the fit can be fine-tuned by adjusting saddle height and the fore-aft position of the saddle. If the reach to the handlebars is too near or too far, the stem can be switched out for a shorter or longer one. Even the crank arms and brake levers can be swapped for a difference size if necessary. The frame’s geometry is fixed, however, so you want to get that right at the start.
There are bike fit calculators online intended to help you get a bike with both the gross fit and the fine-tuning parts right, which can be helpful if you’re purchasing a new bike, but experienced riders who have tried such calculators say they sometimes miss the mark on some recommendations and are not as good as getting fitted by someone with bike fitting expertise.
Recommended Online Bicycle Fit Calculators
Here are two interactive bike fit calculators that we like that you could also try, in case you still aren’t sure after looking at our charts.
Competitive Cyclist https://www.competitivecyclist.com/Store/catalog/fitCalculatorBike.jsp#type
Did our guide help you choose the correct bike size?
Leave a comment and let us know how it helped, or comment with additional questions that you had that we can use to improve the guide.
Allen R. Bussell says
Inches as measurements on one column and centimeters on the other column
It says for 6 foot tall I need 58 cm
58 cm says I need a bike that’s one foot. 10 inches tall
You’re a moron
Road Bike Rider says
In the United States, people typically know their height in feet and inches.
Bicycle frame sizes are measured in centimeters. This means the recommended FRAME size would be 58 centimeters for a 6 foot tall person.
If you only know your height in centimeters because you are outside the United States, then first convert your height in centimeters into feet and inches. You can do this with a Google search like “how tall is 183 cm in feet” and get your height. Then look for a bicycle frame size that is correct for that height.
A 58 centimeter sized bicycle frame would be appropriate for a six foot tall person. If you are 58 centimeters tall, then we cannot help you find a bicycle unfortunately and you should check the toy store instead.
I love it toy store it is lol I can’t stop laughing
OMG best line ever from Road Bike Rider and I just randomly found this post! Poor Jr… I guess we’ll see him at the toy store in the kids isle for bikes! LOL!
Jr is not Canadian.. just a moron
one of the best lines ever.. kudos to road bike rider
James Wheeler says
The general 24 inch bike height requirement is 5’4” or lower, although this does not apply to every person. Taller people could have difficulty cycling on them because their bodies and feet are typically longer and bigger than the bike.
I am 160 cm tall is XL ram and 28 inch bike tooo big or will it be fine? Please answer quick
Good information, but I have to ask, what about those researching and looking to find a good indoor bike for cardio? What would be a good size for those with height questions? Just curious…
Road Bike Rider says
Whether you’re using your bike on a trainer or riding it outside, it should be the same size if it fits you. If you are talking about the size of a dedicated indoor bicycle, most of those only come in one size and you just adjust the seat height to make it comfortable.
Jack Ducan says
This is a very informative article for anyone who looking to buy an inch bike. A 28-inch bike should be for adults only, aged 18 and up. Kid bikes only have a wheel size from 12 inches to 26 inches, and it’s for their safety.
Why the hell when you measure a person’s height in feet and inches, would you give the bike size in freakin centimeters?
Road Bike Rider says
Because bike companies sell them measured by centimeters. If you go to a bike shop, you’ll need to understand how you fit on a bike measured that way whether you like the metric system or not.
Bikes are sold all over the world and most of the world is on the metric system, so that’s why bikes are measured that way in the US even though we don’t really use the metric system for most things except for liter bottles of Coke, etc.
That’s why the chart gives a persons, height and inseam for length leg. I am only 5 foot nine but I have a 33 inch inseam.
Any suggestions for a person with painful hands? I cannot put any pressure leaning forward on my hands, but I love biking.
Mary B says
Thank you for the great information. I always thought a bike was a bike. Short for kids, tall for adults. Now, thanks to you I can make an educated decision when I look for my tricycle.
Again, thanks so very much.