Bike fit, simplified
From body measurements to frame ranges in seconds
Enter your height, inseam, and arm length. Get suggested frame size, saddle height, and stem length for road, gravel, or commuter bikes. Save or print a fit summary for your next shop visit or online order.
Your Measurements
Saved Fits
Enter your measurements and hit Calculate to see suggested ranges.
Suggested Fit
Geometry Targets
| Measurement | Target Range | Why it matters |
|---|
How to measure yourself
Height
Stand barefoot on a flat floor with your back against a wall. Have someone mark the top of your head. Measure from the floor to that mark. Keep the tape straight.
Inseam
Stand with your feet about 15 cm apart. Place a hardcover book between your legs, spine up, pressed firmly against your crotch. Measure from the spine of the book to the floor. This is your cycling inseam.
Arm Length
Hold one arm straight out to the side, parallel to the floor, fingers extended. Measure from the bony point of your shoulder (acromion) to the tip of your middle finger. Round to the nearest half centimeter or quarter inch.
Example fits and common mistakes
Road bike example
A rider 180 cm tall with an 86 cm inseam and 64 cm arms typically fits a 56 cm road frame. Saddle height lands near 74 cm from the bottom bracket. A 100 mm stem keeps reach comfortable for a flexible rider. If you are less flexible or new to drop bars, try a 90 mm stem and a frame with slightly more stack.
Gravel bike example
A 170 cm rider with a 79 cm inseam and 60 cm arms often fits a 54 cm gravel frame. These bikes usually have a taller head tube for a more relaxed position. Stem length can be shorter (80 to 90 mm) to keep steering light on rough roads.
Commuter bike example
A 165 cm rider with a 76 cm inseam and 58 cm arms might start with a small or medium commuter frame. Upright geometry means stack matters more than reach. A 70 to 80 mm stem with flat or riser bars keeps your back and shoulders comfortable.
Common mistakes
- Ignoring torso length. Two people with the same height and inseam can have very different torsos. Arm length helps estimate reach, but always compare stack and reach numbers to the frame's geometry chart.
- Over-reaching. If the suggested stem is over 110 mm, look at a larger frame or one with more stack. Long stems change handling and can strain your back.
- Using standover alone. Standover clearance matters, but modern sloping top tubes change the math. Focus on stack and reach for fit, and check standover as a final safety check.
- Forgetting saddle setback. Saddle height is only part of the picture. How far forward or back the saddle sits affects knee position. Most saddles allow 2 to 3 cm of adjustment on the rails.
Questions people ask
What if I fall between two frame sizes?
For road bikes, the smaller frame is often easier to adjust with a longer stem or higher seatpost. For gravel and commuter bikes, the larger frame can feel more stable. Think about your flexibility and how you plan to ride. If you are not sure, pick the smaller size and fine-tune from there.
Do I need a professional fit instead?
A professional fit is worth it if you ride long distances, have pain on the bike, or are buying an expensive frame. This estimator gives you a solid starting point. You can bring the printed summary to a fitter and save time on basic measurements.
What about women's specific frames?
Some brands design frames with shorter reach and taller stack for average female proportions. Enter your real measurements and compare the suggested stack and reach ranges to any geometry chart. The numbers matter more than the label on the frame.
How do stack and reach affect comfort?
Stack controls how high your handlebars sit relative to the bottom bracket. Reach controls how far forward you have to stretch. A frame with too little stack or too much reach can cause neck, shoulder, or lower back pain. Use the geometry targets table to compare frames before you buy.
Can I save my results?
Yes. Click the Save button after calculating. Your fit is stored in your browser and will still be there next time you visit. You can also print a one-page summary or copy the results to paste into an email or note.