Relative Centrifugal Force (RCF) or g force is the acceleration applied to the sample. RCF is relative to the force of Earth’s gravity and depends on revolutions per minute (RPM) and radius of the rotor.
Centrifugation protocols use Relative centrifugal force (RCF) as this is more precise than RPM because the rotor size might differ, and RCF will be different while the revolutions per minute stay the same. Modern centrifuges have an automatic converter, but older ones do not.
There are several ways to convert g force (RCF) into revolutions per minute (RPM) and vice versa:
1. Use online converters
2. Use the formula:
a. RCF = (rpm)2 × 1.118 × 10-5 × r
b. RPM = √[RCF/(r × 1.118)] × 1,000
3. Use a nomogram (nomograph).
4. Use Beckman Coulter rotors speed converters here.
You can read more information here.