Straight against a wall
Stand straight, ideally barefoot, with your feet about fifteen centimetres apart.
Free bike sizing tool
The right bike starts with the right size.
Road, gravel, mountain, city or kids’ bike: get a clear starting point in seconds, then compare it with the geometry chart for the exact model.
- Instant result
- No data stored
- Centimetres, inches and letters
Find my size
A size suited to every type of riding.
The same rider may prefer a different size depending on the bike, mobility and desired position. These guides explain what to check before buying.
Road bike
Frame size in centimetres, race or endurance position, and choosing between two sizes.
Read the guide →Gravel
Balance stability, handling and long-distance comfort.
Read the guide →Mountain bike
Inches and letter sizes, standover, reach and riding style.
Read the guide →City bike
Upright position, step-through frames, commuting and easy handling.
Read the guide →Kids’ bike
Choose wheel diameter from the child’s current height without buying too large.
Read the guide →A real measurement is better than an estimate.
Inseam directly affects frame size and saddle height. Repeat the measurement twice and keep the most consistent value.
Use a book like a saddle
Raise a firm book between your legs until it makes steady contact, without standing on tiptoe.
Measure to the floor
Measure vertically from the top of the book to the floor, preferably with another person.
Method
How does the calculation work?
The calculator applies an indicative coefficient to your inseam. It is a starting point, not universal geometry: two frames with the same letter can have very different reach and stack.
Understand the measurements| Riding type | Indicative calculation | Main result |
|---|---|---|
| Road | Inseam × 0.66 | Frame in cm |
| Gravel | Inseam × 0.66 | Frame in cm |
| Mountain | Inseam × 0.59 | Frame in cm and inches |
| City / trekking | Inseam × 0.65 | Frame in cm |
| Kids | Total height | Wheel diameter |
Questions to ask before buying.
Always compare a calculated size with the manufacturer’s chart for the exact model.
What if I am between two sizes?
The smaller size often feels more compact and agile; the larger one can feel longer and more stable. Riding style, mobility and the available stem and saddle adjustments should decide.
Are S, M and L identical across brands?
No. Letter sizes are not standardised. Always compare stack, reach, effective top tube and standover height.
Can I choose a bike from total height alone?
Height gives a first range. Inseam improves the estimate, while torso and arm proportions and the desired position still matter.
Should I buy a larger kids’ bike so it lasts longer?
Avoid significant oversizing. A child must be able to start, brake, turn and stabilise the bike confidently today.
Is the calculated saddle height final?
No. It is a starting point. Pedals, shoes, mobility and riding comfort usually require small adjustments.