Difference Between an RCF and an RPM

In a centrifugal process, RCF refers to the force amount on the sample in a centrifuge. RPM describes the rapidity of the centrifuge. An RCF is related to the force of the earth’s gravity, or g -force. It depends on the RPM. Both RCF and RPM are two different units of measuring the centrifugal process. Both of them are related to the measurements of centrifuge, but they are different from each other.


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The difference between an RCF and an RPM is that RCF represents relative centrifugal force. On the other hand, RPM is used for measuring revolution per minute. RPM is the measurement of the exerted force by a rotor due to its rotation. While RPM describes the speed of the rotor created by its revolution.


RCF stands for relative centrifugal force, which is used to measure the force of a rotor. RCF is better known as g force. It indicates the force from a spinning action in the centrifuge. It can be calculated using RPM. The information of centrifugation should be stated either in RCF or g -force.

RPM describes the revolution per minute, and it is the measurement of the fastness of a centrifugal rotation. It stands for the speed of the rotor. RPM doesn’t provide any force-related data of a rotor. It is only related to the speed at which the rotor spins around in the centrifuge. Some of the centrifugation protocols provide instructions in RPM, not in RCF.

Comparison Table

Parameters of Comparison  RCF  RPM  
Definition  RCF refers to the measurement of the force exerted on the sample in the centrifuge.  RPM describes the fastness in the revolution of a rotor.  
Stands for  It stands for Relative Centrifugal Force (g- Force)  It stands for Revolution Per Minute.  
Measurement  To measure the gravitational force of a spinning rotor.  To measure the rotational speed of a moving rotor.  
Calculation  RCF =1.1118× 10 – 5×r×N2  RPM = V[RCF/( r×1.118)]×1,000  
What is it  RCF is generally a measuring unit.  It is not just a unit, it is the measurement of a frequency.  
Usefulness  RCF is more beneficial in a centrifugal process.  RPM is less useful than the RCF.  

What is an RCF?

RCF indicates the force applied to an element in a spinning atmosphere in a centrifugal process. RCF stands for relative centrifugal force and is calculated by multiplying gravitation by force. It’s also known as g-force. Centrifuge manufacturers always publish their information in their instructions manual related to centrifuge for their rotors.

Relative centrifugal force, or RCF, is the unit of measuring the amount of the force of acceleration applied to a sample in a centrifuge. RCF is generally expressed as units of gravity, and it is the measurement of gravitational force generated from the spinning of a rotor. RCF can be calculated by using RPM and also using the dimensions of the centrifuge rotor.

RCF or g force both are used in centrifugation protocols interchangeably. It describes how widely and fastly the rotor is moving. To find the maximum RCF of a rotor, it is necessary to know its maximum speed and its radius. It is equally important to know the distance from the rotation center to the bottom of the rotor during centrifugation. The equation for calculating RCF is, RCF= 11.2×r(RPM/ 1000)². Some centrifugation protocols provide instructions in RPM, not in RCF.

What is an RPM?

In a centrifugal process, RPM stands for Revolution Per Minute. It is the angular speed of the engine in revolutions per minute. It refers to the number of times a rotating object has rotated. The speed of t he object or the frequency of revolution is calculated in miles per hour or metres per second.

The higher the RPM, the quicker the data access method will be. Furthermore, if a whirling item’s RPM is 100, it means the rotor or thing is executing 100 revolutions around a fixed axis in one minute. This unit of measurement tells us how fast the rotor is spinning. A high-speed centrifuge can spin up to 15000 RPM. Additionally, most centrifuges have settings for only RPM.

RPM doesn’t give any force-related data exerted by the rotor. The force amount of the rotor varies according to the type of motor size. If your method details are in RPM and you are using a different size centrifuge, then you should convert it to RCF. RPM is also used to measure the access time on a computer hard disk drive, and it counts the revolutions of the computer hard disk drive.


Main Differences Between an RCF and an RPM

  1. RCF stands for Relative Centrifugal Force. On the other hand, RPM stands for Revolution Per Minute.
  2. RCF is generally known as g force, and it’s a measuring unit. On the other hand, RPM is the measurement of frequency.
  3. RCF refers to the gravitational force of a spinning rotor. On the other hand, RPM refers to the revolutionary speed of a spinning rotor.
  4. Benchtop centrifuges are sold in the market with RPM instructions in them instead of RCF.
  5. According to the rotor size, RCF may differ. While revolution per minute stays the same.
  6. RPM is important to calculate RCF.


  1. https://www.sciencedirect.com/science/article/pii/S0013794404001304
  2. https://www.atsjournals.org/doi/pdf/10.1164/arrd.1985.132.6.1371
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