Formula: RPM = (step frequency × 60) ÷ (full steps/rev × microstepping). Microstepping increases smoothness and positional resolution but does not change the motor's maximum torque or top speed — the driver just sends proportionally more pulses for the same shaft rotation. At very high microstepping (1/16 and above) many drivers need a correspondingly higher step frequency to reach the same RPM, so check your driver's maximum step-pulse frequency rating too.