How this calculator works
A piston travels down one stroke and back up another during each crankshaft revolution. Multiply this total travel by revolutions per second. The cycle type does not change this kinematic result. Connecting-rod length affects the speed waveform and peak acceleration but not the distance covered in a full revolution. This calculation does not set a universal safe RPM.
Formula
Mean piston speed = 2 × stroke × RPM / 60 = stroke × RPM / 30.
Worked example
A 90 mm stroke at 3000 rpm gives 9 m/s average piston speed. A 100 mm stroke reaches 20 m/s at 6000 rpm.
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Frequently asked questions
Is average velocity also positive?
The signed average velocity over a full revolution is zero because the piston returns to its starting point. Average speed measures total travel.
Does this work for a two-stroke?
Yes. The piston still covers two stroke lengths per crank revolution.
Can I obtain peak speed from this?
Not exactly. Peak speed also depends on the connecting-rod and crank geometry.