Velopedia Tools

Bike Fit

Saddle Height & Contact Point Calculator

Build a repeatable fit worksheet from rider inseam, measured saddle position, frame reach/stack and cockpit geometry. The calculator separates a traditional saddle-height starting point from the actual contact-point coordinates that can be measured, adjusted and transferred between bikes.

Rider & saddle

Inseam produces a baseline. Your measured saddle position is the setup worth recording.

Cycling inseam mmFloor to crotch with firm upward pressure, not trouser inseam Measured saddle height mmBB center to the chosen saddle-top reference point Saddle setback mmHorizontal BB-to-saddle-reference offset; positive is behind the BB Knee-angle checkStatic and dynamic angles use different published reference ranges

Frame

Use reach, stack and head angle from the same size and geometry position.

Frame reach mm Frame stack mm Head angle degrees

Cockpit

Resolve the stem clamp first, then add an optional hand-reference offset for the bar/hood/grip position you care about.

Upper stack / spacers mmAlong the steerer above the published frame stack point Stem length mm Stem angle / rise degreesRelative to 90° from the steerer: -6° for a conventional low stem, +6° when flipped upward Hand reference forward offset mmStem clamp to chosen hood/bar/grip reference; positive forward Hand reference vertical offset mmStem clamp to the same hand reference; positive upward

Saddle height: baseline versus actual fit

The traditional LeMond method places the saddle at 88.3% of measured cycling inseam, measured from the center of the bottom bracket to the top of the saddle. It is useful as an anthropometric starting point, not as proof that the resulting position is correct for a particular rider.

Baseline saddle height = inseam × 0.883The calculator keeps this number visibly labeled as a baseline and separately reports the rider's measured saddle position.

Static and dynamic knee angles are not interchangeable

Published bike-fit research commonly uses knee flexion as a saddle-height check, but the measurement protocol matters. A 2020 comparison found that dynamic knee flexion at bottom dead center was about 8° greater than the static measurement and proposed a dynamic BDC reference range of 33–43°. The familiar static Holmes-method range is 25–35°. Velopedia therefore asks which method was used before interpreting an entered knee angle.

Contact points make a fit transferable

A frame label such as 54, Medium or Large does not record where the rider's hands and saddle actually sit. This calculator converts frame reach/stack, headset/spacer stack and stem geometry into BB-relative coordinates, then combines them with the measured saddle position. Those coordinates are far more useful when comparing two bikes or recreating a known-good position.

Stem angle from horizontal = 90° − head angle + stem settingSpacer movement follows the steering axis. Stem length is then resolved into horizontal and vertical components before the selected hand-reference offset is added.

Measurement workflow

1. Measure inseam

Use a rigid book or similar fixture and firm upward pressure. Clothing inseam is not the same measurement.

2. Record the saddle

Measure BB center to a repeatable saddle-top reference and its horizontal setback from the BB. Keep the same reference point next time.

3. Build the cockpit

Use published frame reach/stack, then add the actual spacer and stem configuration. Enter a hand-reference offset only if you can measure it consistently.

4. Transfer, then verify

Recreate the coordinates on another bicycle, then verify pedaling and comfort on the bike. Component shape and rider movement still matter.

Fit-method references: Li et al. (2026) — saddle-height methods · Ferrer-Roca et al. — static vs dynamic knee angle · BikeCAD — applying fit dimensions