Bike size is a combination of measurements that determine the fit and suitability of a bicycle for a rider. This includes the frame size (seat tube length) and wheel diameter, ensuring proper reach, leg extension, and overall handling characteristics. Bike size is fundamentally about matching a rider's measurements to a bike's geometry.
Most manufacturers measure the frame from the center of the crank axle, to the top of the seat tube. Most road bicycles are measured in centimeters (cm), whereas mountain bicycles are generally measured using inches (in).
Sizing nuances can apply across different types of bikes. For example, mountain bikes may prioritize standover height (space between you and the top tube) more than road bikes.
On this page, you will find bike size charts for different bike types: road, mountain, hybrid, time trial, e-bike, and BMX. Also, for different rider types: men, women, and kids.
Adult Bikes Sizes vs Kids' Bike Sizes
Adult bicycles are measured by their frame size. Common wheel sizes for adult bikes include 26-inch, 27.5-inch, and 29-inch.
Kids' bicycles are measured by wheel size rather than frame size. Smaller-wheeled bicycles are lighter and easier to handle for smaller children but will become cramped and difficult to ride as they grow. Kids' bicycles are available with wheel sizes ranging from 12-inch balance bikes (30 cm) up to 24 (ISO 507 mm) or 26-inch (ISO 559 mm) junior bikes.
Therefore, there are two completely different measurement systems between adult and kids bikes. As children grow they’ll start to fit on small adult bikes, but generally, kids 12 yo and younger will fit on bikes that are measured by the size of the wheels.
Women's Bike Sizing Specifics
Overall, there is no critically important difference between men’s and women’s bicycle sizes.
While bike sizing is largely unisex, women's bikes often feature subtle differences to enhance fit and comfort. Some brands offer women-specific models with designs that focus on incorporating better-fitting components. However, both women and men can use the same adult bicycle size charts below to find a bicycle that fits them.
Height
Your standover height is one of the easier ways to get an idea of your frame size. To measure your height, lightly mark the wall with a pencil at the point where the ruler or book (or other flat object) meets your head. Use a tape measure — ideally a metal one that will remain straight — to measure the distance from the floor to the mark on the wall.
What Is Inseam?
Your inseam is the distance from the crotch to the floor. Since inseam is the most important measurement when sizing a bicycle, don't base your inseam simply on your jeans size.
The best way to measure your inseam is to take a measuring tape and calculate the length between just below your crotch and the bottom of your ankle.
Bike Size Charts
Our bike size charts are standardized tables that translate a rider's body measurements into recommended bike frame sizes and wheel diameters. They aim to facilitate proper bike fit, leading to a comfortable, efficient, and enjoyable cycling experience. Our bike size charts are both in imperial and metric systems.
Road Bike Size Chart
This chart suggests the right size of a road bike based on your height and inseam. Make sure to check the manufacturer’s measurements too.
This chart is also applicable for most gravel, cyclocross, and time trial/triathlon bikes.
|
Rider Height |
Rider Inseam |
Frame Size (cm) |
|
148 cm - 152 cm 4'10" - 5'0" |
65 cm - 71 cm 27" - 38" |
XX Small (47 cm - 48 cm) |
|
152 cm - 160 cm 5'0" - 5'3" |
71 cm - 75 cm 28" - 30" |
X Small (49 cm - 50 cm) |
|
160 cm - 168 cm 5'3" - 5'6" |
76 cm - 79 cm 30" - 31" |
Small (51 cm - 53 cm) |
|
168 cm - 175 cm 5'6" - 5'9" |
78 cm - 82 cm 31" - 32" |
Medium (54 cm - 55 cm) |
|
175 cm - 183 cm 5'9" - 6'0" |
81 cm - 85 cm 32" - 33" |
Large (56 cm - 58 cm) |
|
183 cm - 191 cm 6'0" - 6'3" |
86 cm - 90 cm 34" - 35" |
X Large (58 cm - 60 cm) |
|
191 cm - 198 cm 6'3" - 6'6" |
89 cm - 92 cm 35" - 36" |
XX Large (61 cm - 63 cm) |
Women's Road Bike Size Chart
This chart suggests the right size of a road bike for women based on height and approximate inseam. Make sure to check the manufacturer’s measurements too.
This chart is also applicable for most gravel, cyclocross, and time trial/triathlon bikes for women.
|
Rider Height |
Approx Rider Inseam |
Frame Size (cm) |
|
147 cm - 155 cm 4'10" - 5'1" |
65 cm - 71 cm 27" - 28" |
XX Small (44 cm - 46 cm) |
|
155 cm - 160 cm 5'1" - 5'3" |
71 cm - 75 cm 28" - 30" |
X Small (47 cm - 49 cm) |
|
160 cm - 165 cm 5'3" - 5'5" |
76 cm - 79 cm 30" - 31" |
Small (50 cm - 52 cm) |
|
165 cm - 172 cm 5'5" - 5'8" |
78 cm - 82 cm 31" - 32" |
Medium (53 cm - 55 cm) |
|
172 cm - 180 cm 5'8" - 5'10" |
81 cm - 85 cm 32" - 33" |
Large (56 cm - 57 cm) |
Mountain Bike Size Chart
This chart suggests you the right frame and wheel size of a mountain bike based on your height and inseam. Make sure to check the manufacturer’s measurements too.
|
Rider Height |
Rider Inseam |
Frame Size (alpha) |
Frame Size (inches) |
Wheel Size |
|
135 cm - 145 cm 4'5" - 4'9" |
64 cm - 68 cm 25" - 27" |
XX Small |
11" - 12" |
20", 24" or 26" ISO 406 mm, ISO 507 mm or ISO 559 mm |
|
137.0 cm - 155.0 cm 4'5.9" - 5'1.0" |
64.0 cm - 73.0 cm 25.2" - 28.7" |
X Small |
13" - 14" |
26" or 27.5" ISO 559 mm or ISO 584 mm |
|
153.0 cm - 166.5 cm 5'0.2" - 5'5.6" |
72.0 cm - 79.0 cm 28.3" - 31.1" |
Small |
15" - 16" |
27.5" or 29" ISO 584 mm or ISO 622 mm |
|
161.0 cm - 172.0 cm 5'3.4" - 5'7.7" |
76.0 cm - 81.0 cm 29.9" - 31.9" |
Medium |
17" - 18" |
27.5" or 29" ISO 584 mm or ISO 622 mm |
|
165.5 cm - 179.0 cm 5'5.2" - 5'10.5" |
77.0 cm - 84.0 cm 30.3" - 33.1" |
Medium Large |
18.5" |
27.5" or 29" ISO 584 mm or ISO 622 mm |
|
177.0 cm - 188.0 cm 5'9.7" - 6'2.0" |
83.0 cm - 88.0 cm 32.7" - 34.6" |
Large |
19" - 20" |
27.5" or 29" ISO 584 mm or ISO 622 mm |
|
186.0 cm - 196.0 cm 6'1.2" - 6'5.2" |
87.0 cm - 92.0 cm 34.3" - 36.2" |
X Large |
21" - 22" |
27.5" or 29" ISO 584 mm or ISO 622 mm |
|
195.0 cm - 203.0 cm 6'4.8" - 6'7.9" |
92.0 cm - 95.0 cm 36.2" - 37.4" |
XX Large |
23" - 24" |
27.5" or 29" ISO 584 mm or ISO 622 mm |
Women's Mountain Bike Size Chart
This chart suggests the right frame and wheel size of a mountain bike for women based on height and inseam. Make sure to check the manufacturer’s measurements too.
|
Rider Height |
Rider Inseam |
Frame Size (alpha) |
Frame Size (inches) |
Wheel Size |
|
148 - 158 cm 4'10" - 5' 2" |
69 - 73 cm 27" - 29" |
XS |
13" - 14" |
26" or 27.5" ISO 559 mm or ISO 584 mm |
|
158 - 168 cm 5'2" - 5'6" |
74 - 78 cm 29" - 31" |
S |
15" -16" |
27.5" or 29" ISO 584 mm or ISO 622 mm |
|
168 - 178 cm 5'6" - 5'10" |
81 - 86 cm 32" - 34" |
M |
17" - 18" |
27.5" or 29" ISO 584 mm or ISO 622 mm |
|
178 - 185 cm 5'10" - 6'1" |
84 - 89 cm 33" - 35" |
L |
19" + |
27.5" or 29" ISO 584 mm or ISO 622 mm |
Kid's Bike Size Chart
This chart suggests the size of a kids’ bike based on the height and inseam. Make sure to check the manufacturer’s measurements too.
|
Height |
Inseam |
Age |
Suggested Wheel Size |
|
91 cm - 99 cm 36" - 39″ |
38 cm - 46 cm 15″ - 18″ |
2 - 3 years |
12" |
|
94 cm - 112 cm 37" - 44″ |
38 cm - 51 cm 15″ - 20″ |
2 - 4 years |
14" |
|
104 cm - 122 cm 41" - 48″ |
40 cm - 56 cm 16″ - 22″ |
4 - 6 years |
16" |
|
114 cm - 137 cm 45" - 54″ |
48 cm - 64 cm 19″ - 25″ |
5 - 8 years |
20" |
|
124 cm - 150 cm 49″ - 59″ |
58 cm - 71 cm 23″ - 28″ |
8 - 11 years |
24" |
|
142 cm + 56″ + |
64 cm + 25″ + |
10 + years |
26" |
Fitness And Hybrid (City, Commuter) Bike Size Chart
This chart suggests the right frame size for a hybrid bike based on your height and approximate inseam. Make sure to check the manufacturer’s measurements too.
|
Rider Height |
Approx Rider Inseam |
Frame Size |
Frame Size (Alpha) |
|
148 cm - 158 cm 4'10" - 5'2" |
74 - 78 cm 29" - 31" |
33 cm - 37 cm 13" - 14" |
X Small |
|
158 cm - 168 cm 5'2" - 5'6" |
74 - 78 cm 29" - 31" |
38 cm - 42 cm 15" - 16" |
Small |
|
168 cm - 178 cm 5'6" - 5' 10" |
81 - 86 cm 32" - 34" |
43 cm - 47 cm 17" - 18" |
Medium |
|
178 cm - 185 cm 5'10" - 6'1" |
84 - 89 cm 33" - 35" |
48 cm - 52 cm 19" - 20" |
Large |
|
185 cm - 193 cm 6'1" - 6'4" |
87.0 cm - 92.0 cm 34.3" - 36.2" |
53 cm - 57 cm 21" - 22" |
X Large |
|
193 cm - 198 cm 6'4" - 6'6" |
89 cm - 92 cm 35" - 36" |
58 cm - 61 cm 23" - 24" |
XX Large |
Time Trial Bike Size Chart
This chart suggests the right frame size for a time trial/triathlon bike based on your height and inseam. Make sure to check the manufacturer’s measurements too.
|
Rider Height |
Rider Inseam |
Frame Size (cm) |
|
148 cm - 152 cm 4'10" - 5'0" |
65 cm - 71 cm 27" - 38" |
XX Small (47 cm - 48 cm) |
|
152 cm - 160 cm 5'0" - 5'3" |
71 cm - 75 cm 28" - 30" |
X Small (49 cm - 50 cm) |
|
160 cm - 168 cm 5'3" - 5'6" |
76 cm - 79 cm 30" - 31" |
Small (51 cm - 53 cm) |
|
168 cm - 175 cm 5'6" - 5'9" |
78 cm - 82 cm 31" - 32" |
Medium (54 cm - 55 cm) |
|
175 cm - 183 cm 5'9" - 6'0" |
81 cm - 85 cm 32" - 33" |
Large (56 cm - 58 cm) |
|
183 cm - 191 cm 6'0" - 6'3" |
86 cm - 90 cm 34" - 35" |
X Large (58 cm - 60 cm) |
|
191 cm - 198 cm 6'3" - 6'6" |
89 cm - 92 cm 35" - 36" |
XX Large (61 cm - 63 cm) |
Electric Bike Size Chart
This chart suggests the right size for an electric hybrid bike based on your height and approximate inseam. Make sure to check the manufacturer’s measurements too.
Electric Hybrid
|
Rider Height |
Approx Rider Inseam |
Frame Size |
Frame Size (Alpha) |
|
148 cm - 158 cm 4'10" - 5'2" |
74 - 78 cm 29" - 31" |
33 cm - 37 cm 13" - 14" |
X Small |
|
158 cm - 168 cm 5'2" - 5'6" |
74 - 78 cm 29" - 31" |
38 cm - 42 cm 15" - 16" |
Small |
|
168 cm - 178 cm 5'6" - 5' 10" |
81 - 86 cm 32" - 34" |
43 cm - 47 cm 17" - 18" |
Medium |
|
178 cm - 185 cm 5'10" - 6'1" |
84 - 89 cm 33" - 35" |
48 cm - 52 cm 19" - 20" |
Large |
|
185 cm - 193 cm 6'1" - 6'4" |
87.0 cm - 92.0 cm 34.3" - 36.2" |
53 cm - 57 cm 21" - 22" |
X Large |
|
193 cm - 198 cm 6'4" - 6'6" |
89 cm - 92 cm 35" - 36" |
58 cm - 61 cm 23" - 24" |
XX Large |
Women's Electric Bike Size Chart
These charts suggest the right size for an electric hybrid bike for women based on height and inseam. Make sure to check the manufacturer’s measurements too.
|
Rider Height |
Rider Inseam |
Frame Size (alpha) |
Frame Size (inches) |
Wheel Size |
|
148 - 158 cm 4'10" - 5' 2" |
69 - 73 cm 27" - 29" |
XS |
13" - 14" |
26" or 27.5" ISO 559 mm or ISO 584 mm |
|
158 - 168 cm 5'2" - 5'6" |
74 - 78 cm 29" - 31" |
S |
15" -16" |
27.5" or 29" ISO 584 mm or ISO 622 mm |
|
168 - 178 cm 5'6" - 5'10" |
81 - 86 cm 32" - 34" |
M |
17" - 18" |
27.5" or 29" ISO 584 mm or ISO 622 mm |
|
178 - 185 cm 5'10" - 6'1" |
84 - 89 cm 33" - 35" |
L |
19" + |
27.5" or 29" ISO 584 mm or ISO 622 mm |
BMX Race Size Chart
This chart suggests the right frame size, top tube length, stem length, bar rise and width, crank length, and gearing for a BMX race bike based on your height. Make sure to check the manufacturer’s measurements too.
|
Rider Height |
Frame Size |
Top Tube Length |
Stem Length |
Bar Rise |
Bar Width |
Crank Length |
Gearing |
|
132 cm & under 4'4" & under |
Micro |
15" - 16.5" |
Mini: 25mm - 35mm |
2" - 2.5" |
20" - 22.5" |
145 - 155mm |
41-43 / 16 |
|
127 cm - 147 cm 4'2" - 4'10" |
Mini |
16" - 17.5" |
Mini-Mini XL: 30mm - 40mm |
2" - 3.5" |
21" - 23.5" |
155 - 165mm |
41-43 / 16 |
|
137 cm - 155 cm 4'6" - 5'1" |
Junior |
17" - 18.5" |
Mini XL-Expert: 40mm - 45mm |
3" - 5" |
22" - 25" |
160 - 175mm |
42-43 / 16 |
|
152 cm - 163 cm 5'0" - 5'4" |
Expert |
18.5" - 19.5" |
Expert-Pro: 43mm - 48mm |
5" - 7" |
25.5" - 27" |
170 - 175mm |
42-43 / 16 |
|
157 cm - 168 cm 5'2" - 5'6" |
Expert XL |
19.5" - 20" |
Expert-Pro: 43mm - 48mm |
6" - 7" |
25.5" - 27" |
170 - 175mm |
42-43 / 16 |
|
160 cm - 173 cm 5'3" - 5'8" |
Pro |
20" - 20.5" |
Pro: 50mm - 55mm |
7" - 8" |
27" - 28" |
175 - 180mm |
43-44 / 16 |
|
170 cm - 183 cm 5'7" - 6' |
Pro XL |
20.5" - 21.25" |
Pro XL: 50mm - 55mm |
8" + |
28" |
180 - 190mm |
44 / 16 & over |
|
183 cm 6' & over |
Pro XXL |
21.25" - 22" |
Pro XXL: 52mm - 60mm |
8" + |
28" |
180 - 190mm |
44 / 16 & over |
BMX Freestyle Size Chart
This chart suggests the right wheel size and top tube length for a BMX freestyle bike based on your height. Make sure to check the manufacturer’s measurements too.
|
Rider Height |
Wheel Size |
Top Tube Length |
|
71 cm - 92 cm 2'4" - 3' |
12" |
12" - 13" |
|
81 cm - 107 cm 2'8" - 3'6" |
14" |
14" - 14.5" |
|
97 cm - 122 cm 3'2" - 4' |
16" |
16" - 16.5" |
|
117 cm - 142 cm 3'10" - 4'8" |
18" |
18" - 18.5" |
|
142 cm - 158 cm 4'8" - 5'2" |
20" |
18.5" - 20" |
|
152 cm - 163 cm 5' - 5'4" |
20" |
20" |
|
157 cm - 168 cm 5'2" - 5'6" |
20" |
20.25" |
|
163 cm - 173 cm 5'4" - 5'8" |
20" |
20.5" |
|
167 cm - 183 cm 5'6" - 6' |
20" |
20.75" |
|
173 cm - 188 cm 5'8" - 6'2" |
20" |
21" |
|
183 cm+ 6'+ |
20" |
21.25" |
Should I Size Up Or Down?
If you're between sizes, choose the smaller frame size for a more aggressive position. An aggressive geometry also known as "relaxed geometry" or "slack geometry" is when the handlebars are further away from the rider, resulting in a more horizontal, leaned-over position. if the frame is too big, you might be less comfortable and less safe.
Should I Consider Bike Fitting?
Bike fitting is a personalized process that involves a professional analyzing a cyclist's unique body measurements, flexibility, and riding style to optimize their bike setup for maximum comfort, efficiency, and injury prevention.
Benefits of a professional bike fit:
- Improved Comfort: A well-fitted bike eliminates pain points and allows for longer, more enjoyable rides.
- Increased Power and Efficiency: Optimized body positioning maximizes energy transfer while pedaling, leading to faster and stronger riding.
- Injury Prevention: A proper fit reduces repetitive strain and minimizes the risk of overuse injuries.
- Enhanced Handling: A balanced position on the bike improves control and responsiveness.
Key bike fitting adjustments:
- Bike Seat Height: The ideal seat height allows for proper leg extension, ensuring efficient power transfer and reducing knee strain.
- Handlebar Reach: The optimal handlebar position fosters a comfortable upper body posture and responsive handling, minimizing back, shoulder, and neck tension.
- Cleat Position: Correct cleat placement on cycling shoes directly impacts pedaling efficiency and prevents foot and knee discomfort. Cleats are part of a clipless pedal that attaches to the bottom of your cycling shoe – the cleats are what clips into the clipless pedal.
- Body Position: A bike fitter may recommend adjustments to promote a shock-absorbing bend in the arms and a neutral spine to improve stability and comfort, particularly on rough terrain.
How Do I Know My Bike Chain Size?
To know your bike chain size count the number of cogs (gears) on your bike's rear cassette. This determines the chain's width (e.g., 9-speed chains are narrower than 8-speed chains).
Many chains use a master link for easy installation/removal. Make sure your new chain is compatible with your existing master link or purchase the correct type. Consider getting a master link for your chain for easy installation and removal.
Drivetrains with only one front chainring and very wide-range rear cassettes require slightly longer chains. The largest cog/chainring method is still applicable, but you may need to add a bit more length.
If you have a full-suspension bike, check chain length across the full range of suspension travel to ensure it won't get overstretched.
Bike chains are not one-size-fits-all. They are specified by:
- Speeds: The number of gears on your rear cassette (e.g., 8-speed, 11-speed). Chains get progressively narrower as the number of speeds increases.
- Width: Most modern bikes use 3/32" chains. Older bikes and single-speeds sometimes use 1/8" chains.
Methods to determine bike chain size:
- Refer to Your Old Chain:
- If replacing a worn chain, the easiest method is to count the links on your old chain and buy a new one of the same length.
- Note: If your old chain was too long or short, you'll need to use one of the following methods below.
- Largest Cog and Chainring Method:
- Shift to the largest chainring at the front and the largest cog at the rear.
- Thread the new chain around these without going through the rear derailleur.
- Find where the chain overlaps with minimal slack. Mark the link where inner and outer plates meet.
- Add two extra links (1 inch) to this length and cut your chain there.
- Chainstay Measurement Method:
- Measure the chainstay length (center of bottom bracket to the center of the rear axle).
- Multiply that length by two.
- Divide the number of teeth on the largest chainring by 4, and the number on your largest rear cog by 4. Add those results together.
- Add this final number to the doubled chainstay length, plus an additional inch. This is your ideal chain length.