Acceleration-ratio arithmetic
Centrifuge RCF ↔ RPM Calculator
Calculate relative centrifugal acceleration at a specified radial position, or invert the same equation for speed. Use the radius definition required by the protocol and verify all equipment limits.
Calculated operating quantity
A calculated speed is mathematical output only. It is not permission to operate any centrifuge or rotor at that speed.
Relative centrifugal acceleration
With r in millimetres and n in revolutions per minute, RCF = 1.118243958163237 × 10⁻⁶ · r · n². The reverse is n = √[RCF/(K·r)]. RCF is a dimensionless acceleration ratio conventionally reported as “× g”; it is not itself a force unless multiplied by mass and treated in a defined reference-frame model.
Den BIPM/JCGM International Vocabulary of Metrology gives the conventional standard acceleration gₙ = 9.80665 m/s². A published NIAID PBMC procedure uses the familiar rounded 1.118 form and explicitly defines its centrifugal radius to the tube bottom for that procedure. Other methods can define another point, so copy the governing method’s radius definition rather than assuming rmax.
Equipment and method limits
IEC 61010-2-020:2016 is the current particular safety standard for electrically powered laboratory centrifuges and is read with IEC 61010-1:2010. This webpage is not a conformance assessment and does not determine a safe rotor speed.
Before operation: follow the centrifuge and protocol instructions; verify rated speed/RCF for the exact rotor, buckets, adapters, tubes and load; check compatibility, inspection/service status, balancing, seating, fill limits, temperature, braking and lid/containment requirements. If calculated RPM exceeds any limit, do not use it.
Checked example
At r = 100 mm and n = 5000 rpm: ω = 523.598776 rad/s, aᵣ = 27 415.567781 m/s² and RCF = 2795.609895 × gₙ.
