RCF Calculator

Calculation of “G” or RCF (Relative Centrifugal Force)

RCF is dependent on the speed of the rotor and the distance from the centre of the motor drive shaft to the base of the sample tube. Manufacturers will give you the maximum speed and RCF of the rotor and its radius. For any speed other than maximum, you need to calculate the RCF.

If you do not know the radius of the rotor, you will have to measure this. Sometimes this may entail a little bit of guesswork in the case of an angle rotor. The radius is measured from the centre of the rotor to the point that would be the bottom of the sample tube. Take into account, inserts and anytube cushions.

Insert the figures into the formula below or use a nomogram chart, if you have one, with a ruler on two values to determine the third. e.g. RCF and radius to obtain speed or radius and speed to obtain RCF. (A free nomogram chart is available – just call us on 020 8663 4610)

To help you, the formulas are…


To make things really easy, you can use our simple calculator below.

1. Enter Radius (cm)

Radius (cm)

2. Enter either RPM or RCF