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What Size Bike Do I Need? Simple Bike Sizing Charts & Tips

WriterAubrey McShan
15 min read
Couple on the beach ride well-sized bikes with an amusement park in the background at sunset

Stuck on which bike size is the best for you? Learning this can help you feel ready to choose your bike without the overwhelm or confusion.

In this guide, we'll explore four different (but simple) methods for finding the best bike size. You’ll gain a general idea of the appropriate size for mountain bikes, road bikes, hybrid bikes, or electric bikes.

Key Takeaways

What Size Bike Do I Need?

Unlike a kid’s bike, bikes for adults measure by frame size — not wheel size. The bike size you’ll need depends on your height and inseam as well as the type of bike you buy. The bike should be comfortable and provide enough standover height.

There are three general categories of bikes for adults each with its own unique sizing considerations:

  • Road bikes: They're lightweight, fast, and ideal for paved roads.

  • Mountain bikes: These are rugged and designed for off-road trails.

  • Hybrid bikes: They combine elements of both, suitable for diverse terrains.

Expert Tip:

Some bike brands also have unique sizing conventions. The following bike size charts may not be 100% accurate across all bikes.

Road Bike Sizing

Shopping for a road bike? Check out our road bike size chart to help you figure out the bike size that suits you best.

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Road Bike Size Chart
(feet & inches)
Road Bike Size
Road Bike Size
5'0" - 5'3" 152 - 160 29.5 75 19.7 50
5'4" - 5'6" 163 - 168 29.9 - 30.7 76 - 78 20.1 - 20.5 51 - 52
5'7" - 5'9" 170 - 175 31.1 - 31.9 79 - 81 20.9 - 21.3 53 - 54
5'10" - 5'11" 178 - 180 32.3 - 33.5 82 - 85 21.7 - 22.4 55 - 57
6'0" - 6'2" 183 - 188 33.9 - 34.6 86 - 88 22.8 - 23.2 58 - 59
6'3" + 191+ 35.0 - 35.4 89 - 90 23.6 - 24.4 60 - 62
We rounded the centimeter measurements up or down for ease.

Road bikes are typically sized based on their seat tube dimension. Seat tube just refers to the distance between the bottom bracket’s center and the seat tube’s top. You'll need a minimum of 2 inches of clearance between your groin and the seat. This clearance is known as standover height.

Friends celebrate while road cycling together on a paved road

Mountain Bike Sizing

Looking to explore more rugged, rocky terrain? Use our mountain bike size chart to help you find the best fit before you pedal off.

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Mountain Bike Size Chart
(feet & inches)
Mountain Bike Size
Mountain Bike Size
4'10" - 5'1" 147 - 155 24 - 29 61 - 74 14 or less 36 or less
5'1" - 5'5" 155 - 165 25 - 30 64 - 76 15 - 16 38 - 41
5'5" - 5'9" 165 - 175 26 - 31 66 - 79 16 - 17 41 - 43
5'9" - 6'0" 175 - 183 27 - 32 69 - 81 17 - 18 43 - 46
6'0" - 6'3" 183 - 191 28 - 33 71 - 84 18 - 19 46 - 48
6'1" - 6'6" 185 - 198 29 - 34 74 - 86 19+ 48+
We rounded the centimeter measurements up or down for ease.

When shopping for a mountain bike, you’ll also want to factor in stand-over height. You should have 3-5 inches of clearance between your groin and the seat so you have extra space when jumping.

Wide angle view of a mountain biker speeding downhill on a mountain bike track in the woods

Hybrid Bike Sizing

Looking for a bike with the most flexibility? Use our chart below to find the best hybrid bike size.

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Hybrid Bike Size Chart
(feet & inches)
Hybrid Bike Size
Hybrid Bike Size
4'10" - 5'1" 147 - 155 24 - 29 61 - 74 14 36
5'1" - 5'5" 155 - 165 25 - 30 64 - 76 15 38
5'5" - 5'9" 165 - 175 26 - 31 66 - 79 16 41
5'9" - 6'0" 175 - 183 27 - 32 69 - 81 17 43
6'0" - 6'3" 183 - 191 28 - 33 71 - 84 18 46
6'1" - 6'6" 185 - 198 29 - 34 74 - 86 19 48
We rounded the centimeter measurements up or down for ease.

When buying a hybrid bike, make sure you have at least a 1-inch clearance between the seat and groin for maximum comfort. Select a suitable frame, gear system for your terrain, and durable tires for road and trail use. A good hybrid bike balances comfort, speed, and versatility.

Woman in blue outfit in the day rides a blue bike along the beach/shoreline

Find the Right Bike Size Using Other Methods

There’s no one-size-fits-all approach. That’s why we also share three other methods to consider and help you choose the best bike size for you.

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3 Alternative Bike Sizing Methods
Method Method Details How To Use Who It’s For
Custom Measuring for Bike Size Method Uses rider's inseam to recommend bike size Choose the right measurement units for different bike frames: centimeters for hybrid + road bikes and inches for mountain bikes. Riders looking for a more precise fit
Stack and Reach Method Uses bike geometry to recommend bike size Measure the bike's vertical (stack) and horizontal (reach) distances, then compare them to the manufacturer's values Experienced riders or professional athletes looking for high-performance fit
Standover Height Method Measures the distance between the ground and the top tube of the bike frame Measure the distance from the ground to the top tube of the bike frame People with short legs or knee issues who may need more space between the ground and the bike's top tube

Custom Measuring for Bike Size Method

If you're looking for a quick and easy way to figure out the right bike size, the following charts can help. All you need is your height to get started. Simply refer to the chart that corresponds with the type of bike you're interested in and find the size that matches your height.

Step 1: Measure Your Inseam

Diagram featuring the silhouette of a bike rider and explaining where to find the inseam

When you calculate your inseam, you’ll be able to cross-reference the measurement with our size chart or with the specific brand’s bike size chart. Here’s how you find an inseam measurement:

  • Remove your shoes and stand roughly shoulder distance apart. Make sure you’re standing up tall.

  • Take a measuring tape, measure from the floor to your groin in centimeters.

Expert Tip:

Measuring by yourself? Use a retractable measuring tape. You can place a ruler or a book below your groin so you have a marker to make it easier to measure your inseam.

Step 2: Calculate Your Bike Frame Size

Once you’ve calculated your inseam, you can use the following formulas for the specific bike you wish to buy:

  • Hybrid Bike Frame Size (cm) = Inseam Length (cm) × 0.685

  • Mountain Bike Frame Size (inches) = Inseam Length (cm) × 0.225

  • Road Bike Frame Size (cm) = Inseam Length (cm) × 0.665

Next, round up to the nearest whole number and use our size charts to determine your correct bike size. Check out the following example to see the calculation in action:

29 inches = 73.66 centimeters

If you’re shopping for a mountain bike, you will use the following formula: 73.66 (cm) x 0.225 = 16.5735 inches. You can round up to 17 inches.

Stack and Reach Method

The stack and the reach are depicted on a bike on the sidewalk

When achieving the most comfortable riding position is at the top of your list, consider the stack and reach measurement method!

  • Measure the stack: The vertical distance from the middle of the bottom bracket

  • Finds the reach: The horizontal distance between the top of the head tube to the center of the bottom bracket

You can compare this to the brand’s stack and reach measurement. However, not all brands display this measurement.

Expert Tip:

Consider a professional fitting before buying your bike if you’re relying on this method alone.

Standover Height Method

A bike rider standing flat-footed with a bike between their legs, depicting standover height

Knowing the standover height can help you determine if the bike is too tall or too short for you. There are two ways to measure standover height:

  • 1: Place a ruler or book between your legs and measure from the ground to your groin. Be sure to wear your bike riding shoes.

  • 2: If you already own a bike, you can measure from the top tube to the ground while standing in front of the bike seat. Make sure both feet are flat on the ground.

You can compare your standover height to the brand’s measurements.

Frequently Asked Questions

What size bike frame do I need if I’m in-between sizes?

Opt for the smaller size. You can always adjust the saddle and other components to make sure the bike fits well for your height.

How do I know if I’ve purchased the wrong bike size?

You may experience back pain or you may feel too low or too high off the ground. When standing, you’ll want a few inches of clearance between you and the top tube.

What are the different parts of a bike frame?

A close-up image of a bike frame, pointing out key areas for bike measurement like the head tube, top tube, and bottom bracket

Being familiar with the anatomy of a bike frame can also come in handy for the bike sizing techniques we’ll cover later on. Below, we explore the general parts of a bike frame:

  • Top tube: This horizontal bar connects the head tube to the seat tube, providing frame stability.

  • Head tube: It's the frontmost part of the frame that holds the fork and enables steering.

  • Down tube: This large diagonal tube connects the head tube to the bottom bracket, bearing much of the rider's weight.

  • Main triangle: Formed by the top tube, down tube, and seat tube, this is the bike frame's core structure.

  • Bottom bracket shell: This short tube at the lower part of the frame holds the bottom bracket, which allows the crankset to rotate.

  • Seat tube: This vertical tube connects the top tube to the bottom bracket, and the bike's seat post is inserted into it.

  • Rear triangle: Consisting of the chain stay, seat stay, and seat tube, it supports the rear wheel.

  • Chain stay: This pair of tubes run parallel to the chain, connecting the bottom bracket shell to the rear wheel's axle.

  • Seat stay: These tubes extend from the rear of the top tube to the rear wheel, helping to absorb shock.

What are the different types of bikes?

You’ll need to know which type of bike you’re shopping for ahead of time, since this impacts which formula you’ll be using.

Have Fun Out There!

Shopping for a brand-new bike can be an exciting but overwhelming experience. Whether you're browsing in-store or online, taking your height, inseam, and bike preferences into account can help you choose the right bike size for your needs.

At Academy, we offer a wide selection of bikes to choose from, so you can find the perfect fit for your lifestyle. Don't forget to complete your purchase with a bike helmet to keep you safe on the road or trail!