Miniprep spins at 17,900 × g
Convert several spins for a microcentrifuge.
RCF to RPM Calculator
FigranConvert RCF to RPM and rpm to g for your rotor, then copy or print the settings.
- Eppendorf, Thermo and Beckman rotors
- Run time by k-factor
- Copy or print a bench card
Spin setup
11,304 rpm| Step | Protocol | Set | Time |
|---|---|---|---|
| Step 1 | 12,000 × g | 11,304 rpm | — |
Eppendorf 5424 R · FA-45-24-11 · rmax 8.4 cm · no adapter
All steps within the rotor limit (15,000 rpm · 21,130 × g)
× g to rpm conversion chart
Eppendorf 5424 R · FA-45-24-11 · rmax 8.4 cm · no adapter
| × g | rpm |
|---|---|
| 100 | 1,032 |
| 200 | 1,459 |
| 300 | 1,787 |
| 400 | 2,064 |
| 500 | 2,307 |
| 1,000 | 3,263 |
| 1,500 | 3,997 |
| 2,000 | 4,615 |
| 3,000 | 5,652 |
| 4,000 | 6,526 |
| 5,000 | 7,297 |
| 10,000 | 10,319 |
| 12,000 | 11,304 |
| 14,000 | 12,210 |
| 16,000 | 13,053 |
| 20,000 | 14,593 |
| rpm | × g |
|---|---|
| 1,000 | 94 |
| 2,000 | 376 |
| 3,000 | 845 |
| 4,000 | 1,503 |
| 5,000 | 2,348 |
| 6,000 | 3,381 |
| 7,000 | 4,602 |
| 8,000 | 6,010 |
| 9,000 | 7,607 |
| 10,000 | 9,391 |
| 11,000 | 11,363 |
| 12,000 | 13,523 |
| 13,000 | 15,871 |
| 14,000 | 18,407 |
| 15,000 | 21,130 |
Prepared by __________________ Date __________________
RCF calculator examples
Start with a spin and adapt it for your rotor.
Pelleting cells in 15 mL tubes
Set a low-speed cell pellet.
Plasma from whole blood
Convert a non-gel blood tube separation spin.
3,000 rpm to × g for a methods section
Report relative centrifugal force from a recorded speed.
Exosome pellet in a different rotor
Estimate pelleting time on another rotor; acceleration is not included.
Harvesting a 500 mL culture
Convert a bacterial harvest speed.
How to convert × g to rpm for your rotor
The RCF calculator needs only your rotor and the protocol speed.
1Choose a rotor
Select the rotor used for your spin.
2Choose the radius
Choose the tube or adapter and radius used for your force.
3Enter the protocol
Enter the speed, unit and optional time for each step.
4Take the setup to the bench
Copy or print the setup, or export a CSV and methods text.
Relative centrifugal force formula
12,000 × g · r = 8.4 cm → 11,304 rpm
Rated force uses the maximum radius. An adapter can reduce the radius and the force at a given speed.
1 · rmin2 · rav3 · rmax
Centrifuge k-factor and run time
70 min × 220 / 356 = 43 min
This estimate applies to pelleting in the same medium, not density gradients, and does not account for acceleration or braking.
References: Eppendorf 5424 R manual, §9.7.1 · Beckman Coulter, Using k-Factor
RCF calculator FAQ
How do I convert rpm to g?
Multiply 1.118 × 10⁻⁵ by the radius in cm and rpm squared. At 14,000 rpm and 8.4 cm, the force is 18,407 × g.
What is 300 × g in rpm?
It depends on the radius: 1,787 rpm at 8.4 cm, 1,264 rpm at 16.8 cm, or 1,221 rpm at 18 cm.
What does RCF mean, and is it the same as × g?
RCF is relative centrifugal force, expressed as a multiple of gravity in × g. RPM depends on the rotor radius.
What is 10,000 × g in rpm on a microcentrifuge?
At 8.4 cm use 10,319 rpm; at 8.6 cm use 10,198 rpm; at 7.2 cm use 11,146 rpm.
Which radius should I use: rₘₐₓ, rₐᵥ or rₘᵢₙ?
Use rₘₐₓ unless the protocol specifies another radius. Use the radius for the actual tube and adapter.
Why do RCF calculators give slightly different answers?
Some use 1.12 × 10⁻⁵ instead of 1.118 × 10⁻⁵, a difference of about 0.2%. Radius choice and units can cause larger differences.
How do I adjust centrifugation time for a different rotor?
For pelleting in the same medium, multiply the original time by the new k-factor divided by the original k-factor at the actual speeds. This does not apply to gradients.
My rotor is not in the list. What radius do I enter?
Use the radius in your rotor manual or measure from the axis to the bottom of the tube. Select Custom radius to enter it.