Bike Fit Frame & Saddle Calculator
Body measurements to bike starting points
Estimate frame and saddle setup
Result
Calculation summary
Enter values to see the result
Live fit preview
Body proportions guide the first setup
Frame range
54.8–57.8 cm
Saddle height
74.2 cm
Reach profile
Neutral-reach starting point
The diagram separates frame range, saddle height and reach profile instead of pretending one size fits every brand.
How to use this calculator
- 1Measure height, cycling inseam and arm span consistently.
- 2Choose the intended bicycle type and enter actual crank length.
- 3Compare the estimated range with the manufacturer's stack, reach and standover chart.
Formula
saddle-BB = inseam × 0.883; pedal reference = inseam × 1.09
Two common saddle references and a bike-type frame factor are shown as starting points.
Calculation steps
- Normalize measurements to centimetres.
- Calculate frame, saddle and standover references.
- Compare arm span with height for a reach starting profile.
Worked example
An 82 cm inseam gives a 72.4 cm LeMond saddle height from the bottom-bracket center.
Assumptions
- Measurements are taken consistently.
- Frame sizing conventions vary by brand.
- Ape index is only a reach cue.
- Dynamic movement and symptoms are not modeled.
Sources
Frequently asked questions
Can I buy a frame from this result alone?
No. Compare the range with the exact brand's geometry and test the bicycle.
Where is saddle height measured?
The LeMond result is from bottom-bracket center to the saddle reference point along the seat tube.
Why show two saddle methods?
They use different references; the visible difference helps expose uncertainty.
Does reach profile prescribe a stem?
No. It only signals which geometry direction deserves closer comparison.