Centrifuge RCF ⇄ RPM Calculator: convert g-force and spin speed with a rotor library
Stop guessing RCF ↔ RPM
Protocols quote spin steps as × g (relative centrifugal force), but your centrifuge dial reads RPM — and the conversion depends on your rotor’s radius, so a single magic number doesn’t work. This tool does it properly: pick your rotor (or enter the radius), type either value, and the other updates instantly.
Use it now
Found a bug or want a feature? Tell us — we read everything.
What it does
- Bidirectional conversion — edit RPM or RCF (× g) and the other recalculates live; a slider drives the speed.
- Rotor library — common rotors (Eppendorf, Thermo Sorvall, Beckman, plus generic microfuge / swinging-bucket / plate rotors) preload a typical radius, or enter your own.
- Live rotor visualization — a top-down rotor that spins faster as RPM rises, with the radius marked.
- Extras — tip speed (m/s) and angular velocity (rad/s).
The formula
RCF = 1.118 × 10⁻⁶ × r(mm) × RPM² (the textbook constant 1.118 × 10⁻⁵ is for
radius in cm; this tool uses millimetres). Verified against the Eppendorf 5424
(84 mm → 21,130 × g at 15,000 rpm) and the 5810 A-4-62 swing rotor
(180 mm → ~3,220 × g at 4,000 rpm).
Rotor radii in the library are typical values — always confirm the exact rmax for your rotor against its manual for critical work. The conversion itself is exact for whatever radius you enter.
Embed it on your site
<link rel="stylesheet" href="https://www.37degrees.io/interactive-tools/centrifuge-rcf/styles.css" />
<div id="centrifuge-widget-embed"></div>
<script>
// Optional: window.CENTRIFUGE_THEME = "light";
</script>
<script src="https://www.37degrees.io/interactive-tools/centrifuge-rcf/widget.js"></script>Credits
Built and maintained by 37degrees. Standard centrifugation math — no third-party libraries, no data leaves the browser.