Frame size calculator: find the right bike size
The right frame size is essential for cycling comfort and enjoyment. A bike that's too small gives a cramped ride; one that's too large is hard to control. On this page we explain simply how to calculate the perfect frame size.
What is frame size?
Frame size is the length of the seat tube of the bike frame, measured from the center of the bottom bracket to the top of the seat tube. This measurement is expressed in centimeters and largely determines whether a bike fits you.
A correct frame size ensures:
- Comfortable riding position
- Good leg extension while pedaling
- Safe and manoeuvrable handling
- Prevention of knee and back problems
Calculating frame size based on leg length
The most reliable method to determine your frame size is measuring your inseam length. Here's how:
- Step 1: Stand with your back against a wall, barefoot, with your feet about 15 cm apart.
- Step 2: Place a book firmly between your legs, as if sitting on a saddle.
- Step 3: Measure the distance from the top of the book to the floor.
- Step 4: Multiply this value by 0.66 for a men's bike or 0.65 for a women's bike.
The result is your ideal frame size in centimeters. When in doubt, always choose the smaller size - a slightly smaller bike is more comfortable than one that's too large.
Frame size chart by bike type
Use these guidelines per bike type:
- City bike and hybrid: Frame size = inseam x 0.66
- Road bike: Frame size = inseam x 0.67
- Mountain bike: Frame size = inseam x 0.57 (MTBs run smaller)
- Dutch bike: Frame size = inseam x 0.65
Example: With an inseam of 82 cm, for a city bike: 82 x 0.66 = 54 cm frame size.
Bike sizes in inches
Many bike brands use inches instead of centimeters. One inch is 2.54 cm. To find the frame size in inches, divide the centimeters by 2.54. A frame size of 54 cm equals approximately 21 inches.
Wheel size (in inches) is different from frame size. Wheel size indicates the diameter of the wheels: 26 inch, 27.5 inch, 28 inch or 29 inch for adult bikes.
Not sure about the size?
If you're between two sizes, we recommend choosing the smaller frame size. A smaller bike is easier to adjust with a longer seat post and higher handlebars. A bike that's too large is harder to correct.
Our customer service team is happy to help you choose the right size. Email support@tormino.com with your inseam length and the type of bike you're looking for, and we'll give you personal advice.
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Frequently asked questions
How do I measure my leg length most accurately?
The most accurate method is the book method: place a book between your legs against a wall and measure from the top of the book to the floor. Measure barefoot and stand up straight.
Can I calculate frame size based on my height?
Height gives a rough indication but is less reliable than leg length. Two people of the same height can have different leg proportions. Use inseam length for the most accurate result.
What if I'm between two sizes?
Choose the smaller size. A slightly smaller bike can be adjusted with a longer seat post and stem extender. A bike that's too large is harder to make comfortable.
Does frame size differ by bike type?
Yes, a mountain bike runs smaller than a city bike. A road bike has a different ratio again. Use the correct formula for each bike type for the best result.
Do you offer bikes in different frame sizes?
Yes, in our bike collection you'll find bikes in various frame sizes. Filter by frame size or contact our customer service team for tailored advice.
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