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Practical Centrifuge

Centrifuge converter (rpm ↔ RCF ×g)

Convert between centrifuge speed (rpm) and relative centrifugal force (RCF, ×g) using rotor radius. Supports radius units (mm/cm/in), a quick reference table, and copy/export features.

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How to use (3 steps)

  1. Pick an example or choose a mode (rpm → ×g / ×g → rpm).
  2. Confirm the radius (distance from rotor center to sample) and unit (mm/cm/in).
  3. Enter rpm or ×g to see the converted result.

RCF depends on how radius is defined (rmax/ravg, etc.). Use the value provided in your rotor manual if possible.

Quick protocol workflow (when switching centrifuges)

  1. Convert the original protocol rpm to RCF (xg) using the original rotor radius.
  2. Keep that target RCF, then convert back to rpm with your destination rotor radius.
  3. Record both the radius definition and units (mm/cm/in) in your note so the run can be reproduced.

This keeps force level consistent across rotors better than copying rpm alone.

Input (radius, rpm/RCF)

What to solve for
Radius (important)

Distance from rotor center to the sample position. Use your rotor manual if possible.

Custom radius
RPM (speed)

Result (conversion)

Formula used (coefficient 1.118×10^-5)
RCF(×g) = 1.118×10^-5 × r(cm) × rpm^2
rpm = sqrt( RCF / (1.118×10^-5 × r(cm)) )
r(cm) = r(mm) / 10
r(cm) = r(inch) × 2.54
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How it’s calculated

This tool converts radius to cm and uses a commonly used formula.

RCF depends on how radius is defined (rmax/ravg, etc.). If results look off, recheck units (mm/cm/in) and your radius definition.

How to use this calculator effectively

This guide helps you use Centrifuge converter (rpm ↔ RCF ×g) in a repeatable way: define a baseline, change one variable at a time, and interpret outputs with explicit assumptions before you share or act on results.

How it works

The page applies deterministic logic to your inputs and shows rounded output for readability. Treat it as a comparison workflow: run one baseline case, adjust a single parameter, and measure both absolute and percentage deltas. If a result seems off, verify units, time basis, and sign conventions before drawing conclusions. This approach keeps your analysis reproducible across teammates and sessions.

When to use

Use this page when you need a fast estimate, a classroom check, or a practical what-if comparison. It works best for planning and prioritization steps where you need direction and magnitude quickly before investing in deeper modeling, manual spreadsheets, or formal external review.

Common mistakes to avoid

Interpretation and worked example

Run a baseline scenario and keep that result visible. Next, modify one assumption to reflect your realistic alternative and compare direction plus size of change. If the direction matches your domain expectation and the size is plausible, your setup is usually coherent. If not, check hidden defaults, boundary conditions, and interpretation notes before deciding which scenario to adopt.

See also

FAQ

What is RCF (×g)?
It is the relative centrifugal force expressed as a multiple of gravitational acceleration (g). Protocols often use ×g to compare conditions across different centrifuges and rotors.
Which radius should I use?
Use the distance from the rotor center to the sample position. Rotor manuals often list it as “radius”, “rmax”, or “ravg”. Use the manual value if possible.
Should I use rmax or ravg?
Follow your protocol definition. If unsure, rpm is fine when using the same rotor. When changing rotors, using the manual value (often ravg) is usually safer for conversions.
I want to reproduce an rpm protocol on a different centrifuge.
RCF changes with radius even at the same rpm. Convert the original rpm to ×g first, then convert ×g back to rpm using your rotor radius.
My result differs from other sites.
Differences can come from constants, the definition of g, and how radius is defined (cm/mm, rmax/ravg). This tool uses a common formula with radius in cm.
Can I enter 0 rpm or 0 ×g?
Yes. Entering 0 gives 0 as the result (radius must be non-zero).
It feels too strong/too weak.
Common causes are unit mistakes (mm vs cm) and radius definition differences. Recheck units and radius.

How to use Centrifuge converter (rpm ↔ RCF ×g) effectively

What this calculator does

This page is for estimating outcomes by changing inputs in one controlled workflow. The model keeps your focus on variables, not output shape. Start with stable assumptions, then test sensitivity by changing one key input at a time to observe directional impact.

Input meaning and unit policy

Each input has an expected unit and a typical range. For reliable interpretation, check whether you are using the same unit system, period, and base assumptions across all runs. Unit mismatch is the most common source of unexpected drift in numeric results.

Use-case sequence

A practical sequence is: first run with defaults, then create a baseline log, then run one alternative scenario, and finally compare only the changed output metric. This sequence reduces cognitive load and prevents false pattern recognition in early experiments.

Common mistakes to avoid

Avoid changing too many variables at once, mixing incompatible data sources, and interpreting a one-time output without checking robustness. A single contradictory input can flip conclusions, so keep each experiment minimal and document assumptions as part of your note.

Interpretation guidance

Review both magnitude and direction. Direction tells you whether a strategy moves outcomes in the desired direction, while magnitude helps you judge practicality. If both agree, you can proceed; if not, rebuild the baseline and verify constraints before deciding.