How do you convert RPM to RCF?

RCF = 1.118 × 10⁻⁵ × r × RPM², where r is the rotor radius in centimeters. Enter your rotor radius and speed and the calculator returns the relative centrifugal force in ×g.

Should I use RPM or RCF to reproduce a protocol?

Always RCF (×g). RPM produces different forces on different rotors because force depends on radius. Two centrifuges at the same RPM apply different g-forces if their rotor radii differ, so a published protocol should be matched by RCF.

Where do I find my rotor radius?

It is on the rotor or centrifuge specification sheet, listed as the radius (r max), the distance from the rotor axis to the bottom of the tube. Use r max for the force at the tube bottom.

RCF ⇄ RPM Calculator

Convert between rotor speed (RPM) and relative centrifugal force (RCF, ×g) using your rotor radius. Reproduce any centrifugation protocol correctly, by force, not speed.

Rotor radius (mm)

The distance from the rotor center to the tube bottom, on the rotor or centrifuge spec sheet.

Speed (RPM)

Relative Centrifugal Force

1,789 × g

Formula: RCF = 1.118 × 10⁻⁵ × r(cm) × RPM². Always convert protocols by RCF (×g), not RPM, RPM is rotor-dependent.

Shop Centrifuges →Centrifuge Buying Guide

Frequently asked

How do you convert RPM to RCF?: RCF = 1.118 × 10⁻⁵ × r × RPM², where r is the rotor radius in centimeters. Enter your rotor radius and speed and the calculator returns the relative centrifugal force in ×g.
Should I use RPM or RCF to reproduce a protocol?: Always RCF (×g). RPM produces different forces on different rotors because force depends on radius. Two centrifuges at the same RPM apply different g-forces if their rotor radii differ, so a published protocol should be matched by RCF.
Where do I find my rotor radius?: It is on the rotor or centrifuge specification sheet, listed as the radius (r max), the distance from the rotor axis to the bottom of the tube. Use r max for the force at the tube bottom.