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Centrifuge RPM & Relative Force from Rotor Radius

Convert between RPM and relative centrifugal force using the entered rotor radius and the conventional rounded coefficient.

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Enter the known values in the units shown. Results update as you type.
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At radius 10 cm and speed 3,000 rpm, the retained formula gives an approximate relative centrifugal force of 1,006.2 ×g.

RCF = 0.00001118 × radius in centimetres × RPM²

Enter these known values and leave the other values blank.

The coefficient 0.00001118 is the conventional rounded conversion. The result is not an exact metrological conversion.
Radius is positive and measured from the rotation axis to the relevant sample position. Different positions in a tube have different radii and forces.
RPM and relative force are nonnegative. This calculation does not establish safe equipment speed or choose a centrifugation protocol.

At the same RPM, relative force is proportional to radius. RPM alone cannot identify the force at the sample.

Use the radius appropriate to your protocol and rotor documentation, such as the maximum sample radius when the specified force is RCF max.

Bookify allows the stationary limit with zero RPM and relative centrifugal force.