What Size Bike Do I Need?

Last updated 22. July 2020

Are you looking to invest in a new bike? Perhaps you’re investing in your first bike and are confused about what size of bike to buy? Bikes come in a wide selection of different sizes and styles. Whether you’re looking for a road bike or a mountain bike, you’ll need to decide what size of frame and wheels to buy.

This article will help to decide what size of bike you need. We’ll look at why bike size matters and help you to choose the correct size of frame and wheels for your height. Also if you are a complete beginner and you don’t even know how to ride a bike, we got you covered! Check out our bike riding for beginners tutorial here!

Bike sizes

Choosing the right size of bike for your needs will depend on a variety of things. You should take into account the type of bike you wish to purchase, as well as your height and riding style. Bicycles are available in many different shapes and sizes, and the kind of bike you choose will often come down to personal preferences. Mountain bikes, road bikes, hybrids, and electric bikes come in different sizes, and all have slightly different sized wheels and frames.

A bike that fits correctly will be more comfortable and fun to ride. If you’re trying to ride a bike that’s incorrectly sized for your height, this could be very tiring and may also be dangerous.

The size of the bike you choose will vary slightly for different styles. If you want a mountain bike, you’ll likely ride more aggressively than on other bike types. You’ll, therefore, need a flexible and maneuverable bike for all the ups and downs and jumps that you’re likely to perform. For this reason, you may prefer a slightly smaller size.

what bike size do I need
If you’re looking for a road bike and plan to do long distance cross country cycling or even racing its best to go for a bike with slightly larger wheels as this will help you to cover a greater distance with less effort.

Often there is no right or wrongs when it comes down to size, as long as you get a bike that you can comfortably ride, it’s likely to be the right size. It often comes down to personal preference, and if you’re able to test ride a bike before buying it, that’s an advantage as you’ll be able to check that it feels comfortable.

How Are Bike Sizes Measured?

Bikes generally have two different measurements, the size of the frame and the size of the wheels. There are also many other measurements that you may be interested in, such as the distance between the two wheels or the chain length. When bikes are being sold, their frame size and wheel size are usually the most critical measurements.

The wheels’ size is measured in inches, and this measurement includes the tire, rim, and wheel. The measurement is taken from the top of the tire to the ground and is usually 26, 27, or 29 inches. Smaller sized wheels are available for children’s bikes. Sometimes the wheel size will also be given as the diameter of the wheel.

Bike frames are measured by the seat tube, which is the measurement of the main tube, which runs from the seat to the chain. Bike seats are adjustable, so this measurement is generally taken from where the seat post attaches to the frame, instead of from underneath the seat.

The measurements of the frame differ by brand. They can even vary between the make and model of bikes with the same manufacturers. Some bikes will have descriptive sizes, e.g., small, medium, or large.

What Size Road Bike Do I Need?

Road bikes are very popular for long-distance cycling on flat, smooth surfaces as well as for weekday commutes to work. Road bikes are available in a wide selection of frame and wheel sizes. They have been designed to fit a range of different heights.

You’ll also have a choice of frame styles when choosing a road bike as they either have a crossbar or open-frame design. Road bike frames are measured in inches and are generally available in sizes of between 14 inches and twenty-two inches. To work out what size of road bike you need, you should measure your height, and if you plan to buy a bike with a crossbar, you should also measure your inside leg.

What Size Bike Do I Need for My Height?

To measure your height, you can stand against a wall and make a mark above your head. If you find this task difficult, ask someone to help you. You’ll then be able to measure from the mark to the ground.

After you’ve measured your height, you can then find the measurement of your inside leg by standing against a wall. Place a book between your legs and into your groin. Make sure that the book is flat against the wall and then measure from the book, down to the floor.

You can then use these measurements and the table below to work out what size of bike you need.

Frame Size

Riders Height

Riders Inside Leg


147-156 cm

63-84 cm


157- 166 cm

67-88 cm


167- 177 cm

72-93 cm


178- 184 cm

77-98 cm


185- 200 cm

83-104 cm

If your height is between a size range, for example, if you’re 156.5cm tall, you may be wondering whether to go for a frame that’s 14” or one that’s 16”. To help you decide, it would be beneficial to try both sizes and see which one feels more comfortable.

To help you make this decision, you can also measure your ape index, which will tell you your reach. To get this measurement, measure your arm span from the tips of the fingers on one hand across your back to your fingers on the other hand. You can then subtract your height from this measurement. If you’re left with a positive number, it’s a good idea to go for the larger sized bike. A negative number would indicate that you need the small of the two sizes.

Why Does Bike Size Matter?

The size of your bike matters as having the right sized bike will make cycling a lot easier. It’s more enjoyable and comfortable to ride a bike that’s the correct size. In general bikes have different sized wheels and frames. Bike wheels usually come in three different sizes; 26 inches, 27.5 inches, and 29 inches. You’ll sometime notice that 27.5-inch wheels are called 650B.

It’s essential to choose the correct size of wheel for your height as this will affect your riding position and style and how comfortable you feel while cycling. The size of a bikes wheel will determine its rolling resistance. The rolling resistance is how far the bike will travel on one turn of the pedals. Having larger wheels will allow you to go further with less effort if you’re on a road bike and will also allow you to overcome bigger obstacles when riding a mountain bike.

If you’re cycling a mountain bike with a twenty-six-inch wheel and there’s suddenly a log in the middle of the track, it will be harder to get over on a bike with a smaller wheel. This is because the log will meet your bike higher up the wheel than it would if you were riding a bike with a 27.5 inch or 29-inch wheel.

When mountain biking was first invented, they all had 26-inch wheels, which was thought to be a lighter option. Some people prefer a smaller wheel as the bikes are lighter and more agile. They are likely to be faster, making steep climbs easier. Mountain bikes with smaller wheels are also able to navigate trails with many turns more effectively.

If you’re a beginner who’s looking to purchase your first mountain bike, you may like to choose one with a wheel that’s 650B/27.5 inches. This will give you the benefit of speed with more control and stability then a smaller wheel can offer.

What Bike Size Should I Get?

The size of bike you choose should depend on your height and your inside leg measurement. As well as on the type of bike you’re choosing. The following formulas help you determine the size of the frame you need for a city bike, a mountain bike, and a road bike.

City Bike

If you want to buy a city bike, measure your inside leg in centimeters and then multiply this by 0.685 to get your frame size.

Inside leg X 0.685 = Frame size for a city bike

Mountain Bike

If you’re looking for a mountain bike, your inside leg measurement in cm should be multiplied by 0.66 to work out your frame size.

Inside leg (cm) x 0.66 = Frame size for a mountain bike

As you probably know, mountain bikes can be pretty expensive so you can check out our recommendation for the best mountain bikes under $500 here!

Road Bike

If you decide that a road bike is more your style, you can multiply your inside leg measurement by 0.70 to get the desired frame size.

Inside leg in cm x 0.70 = Frame size for a road bik

Electric bike

Well, there are no really many sizes for electric bikes, but if you are considering to get one of these amazing time and energy saving things, make sure to check out our electric bike buying guide!

What Size Bike Frame Do I Need?

As well as the frame size, a measurement that’s often used when buying and selling bikes is the standover height. This is a measurement of how tall the frame is from the ground. The standover height is measured from the top of the top-tube to the ground. When choosing what size of bike you need, you should also allow at least an inch of clearance between you and the frame.

To calculate your standover height, you should find your leg measurement and then minus an inch. When measuring your height and inside leg measurements, it’s a good idea to do this while wearing your shoes as you’ll always wear shoes to ride a bike.

It’s important to leave about an inch gap between you and the frame in case you have to jump off your bike quickly. Having a bit of extra space will help reduce the likelihood of injuries occurring.

How Do I Know What Size Bike I Need?

The simplest way to determine the size of bike is to measure your height and then use the details below to decide what size of frame you need to buy.

If you’re between 4’11” and 5’3″, you should choose a bike frame between 13 and 15 inches. This size of bike is for a petite woman or a teenager.

At a height of 5’3″ to 5’7″, you’ll need to purchase a bike with a frame that’s 15 to 16 inches. This is the average size of bike for a woman.

A taller woman or a small man whose height is 5’7″ to 5’11” will need a bike with a 16 to 17 inches frame.

For taller people of 6’0″ to 6’2″choose a 17 – 19-inch frame.

If you’re 6’2″ to 6’4″ you’ll need a frame that’s 19 – 21 inches

And finally for those who are over 6’4″ choose a frame of 21+ inches


If you follow the instructions above and correctly, calculate your height and inside leg measurements, you’ll easily be able to find a bike that’s a good fit for you. You may like to buy a bike from a bike shop, which will give you the added advantage of being able to take it for a test ride.

However, it is possible to get the correct size of bike online. If you have miscalculated your bike size and have a bike that’s slightly too large or too small, there are a few things you can do to rectify the situation.

The first thing you should do is ask your merchant if you can return the bike and get one that’s a different size. You could also try adjusting the seat. You should be able to comfortably touch the ground with your tiptoes when sitting on the seat. You can adjust your seat by tilting it to the front or rear to change your riding position. You can also move it up or down if you need to you can buy a longer seat post to give you some extra height.

Remember that riding a different bike may feel odd at first, and you may have to give yourself time to get used to it. If your new bike has larger wheels or a crossbar and your previous bike didn’t, it may feel too large or a bit strange.

Also, Global Cycling Network published this amazing video guide on how to choose the correct bike size, and you can watch it here:

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