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Centrifuge RCF and RPM Converter

Convert between g-force and rotor speed, which is the only way to reproduce a protocol on a different machine.

Convert

Value (RPM or g)

Rotor radius (mm)

How it works

RCF equals 1.118 times ten to the minus five, times the rotor radius in millimetres, times RPM squared. Protocols quote g because it is machine independent; your centrifuge dial reads RPM, which is not.

Worth knowing

Radius is measured from the axis to the bottom of the tube at its angle in the rotor, not to the rotor edge. Getting this wrong is the usual reason a protocol fails to transfer.
A fixed-angle and a swing-out rotor at the same RPM give different RCF because the radius differs.
Always record g in a protocol, never RPM. RPM means nothing without the rotor.