20,000 × g to RPM

20,000 × g at common rotor radii

How to set a centrifuge to 20,000 × g

1. Find the radius of your rotor in cm, from the centre of the rotor to the bottom of the tube. It is printed on the rotor or in its manual. Enter it above; 20,000 × g is already filled in.
2. The RPM to set is shown as you type. The table below gives it for common radii.
3. Set the centrifuge to that RPM, or enter the × g directly if it has an RCF mode.

Frequently asked questions

How many RPM is 20,000 × g?

It depends on the rotor. At an 8.5 cm radius, typical for a microcentrifuge, 20,000 × g is about 14,507 RPM; at 10 cm it is about 13,375 RPM. The formula is RPM = √(RCF ÷ (1.118 × 10⁻⁵ × r)), with r in cm.

Is 20,000 g the same as 20,000 RCF?

Yes. RCF, relative centrifugal force, is written as a multiple of g, so 20,000 × g, 20,000 RCF and 20,000 g all mean the same force.

Why does a bigger rotor need fewer RPM?

Force grows in proportion to the radius, so a rotor twice the size reaches 20,000 × g at 10,258 RPM of the speed (1 ÷ √2, about 71%).