In centrifugation the clearing factor or k factor represents the relative pelleting efficiency of a given centrifuge rotor at maximum rotation speed.
(in svedbergs): The value of the clearing factor depends on the maximum angular velocity
of a centrifuge (in rad/s) and the minimum and maximum radius
of the rotor: As the rotational speed of a centrifuge is usually specified in RPM, the following formula is often used for convenience:[1] Centrifuge manufacturers usually specify the minimum, maximum and average radius of a rotor, as well as the
For runs with a rotational speed lower than the maximum rotor-speed, the
factor has to be adjusted: The K-factor is related to the sedimentation coefficient
is the time to pellet a certain particle in hours.
is a constant for a certain particle, this relationship can be used to interconvert between different rotors.
, the time to pellet in the other rotor, can be calculated.
In this manner, one does not need access to the exact rotor cited in a protocol, as long as the K-factor can be calculated.