Work out bike frame size instantly with clear inputs, formula shown and shareable results.
Frame size is derived from inside leg, not height, because leg-to-torso proportions vary widely. The standard multipliers are 0.665 of inseam for road, 0.635 for hybrid and 0.57 for mountain bikes, and saddle height is 0.883 of inseam measured to the pedal spindle.
Frame sizing
frame size = inseam x type factor; saddle height = inseam x 0.883 (LeMond method)
Two riders of the same height can differ 8 cm in leg length. The saddle-to-pedal relationship depends on leg length alone.
The LeMond formula, a long-standing fitting heuristic. It gives a starting point; final saddle height is set by knee angle observation.