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Centrifuge Concentration Calculator

The Centrifuge Concentration Calculator estimates the concentration of material recovered after centrifugation from the recovered amount and the final resuspension volume. It is useful when a pellet, precipitate, or concentrated fraction is resuspended and you need a quick mass-per-volume value for downstream setup.

The calculator also reports the concentration fold-change relative to an optional starting concentration. That comparison can help with sample normalization, assay planning, or deciding whether an additional concentration step is necessary. Because centrifugation recovery can vary with rotor, speed, sample chemistry, and handling, the result describes the measured recovered material rather than predicting recovery efficiency.

Recovered sample

mg
mL
mg/mL
Result
—
Final concentration
Concentration fold-change—
Recovered amount—
Final volume—

1. Enter recovered material
Use the measured mass of material present in the final centrifuged fraction.

2. Enter final resuspension volume
Use the actual liquid volume after the pellet or fraction has been resuspended.

3. Add a starting concentration if useful
This optional value is used only to calculate the fold-change in concentration.

4. Review the concentration
The primary result is reported as recovered amount divided by final volume.

5. Check the fold-change
When a starting concentration is supplied, compare the final concentration with that baseline.

Final concentration = Recovered amount / Final resuspension volume
Fold-change = Final concentration / Starting concentration

Where:

  • Recovered amount = measured mass in mg
  • Final resuspension volume = final liquid volume in mL
  • Starting concentration = optional baseline concentration in mg/mL

Assumptions: The recovered amount is assumed to be distributed uniformly in the stated final volume. The calculator does not estimate material lost during centrifugation.

What the result means

The recovered fraction is four times as concentrated as the stated starting sample.

Use the result as a planning or calculation aid and confirm protocol-specific assumptions before laboratory use.

Given

  • Recovered amount = 18 mg
  • Final resuspension volume = 1.5 mL
  • Starting concentration = 3 mg/mL

Calculation
Final concentration = 18 / 1.5 = 12 mg/mL
Fold-change = 12 / 3 = 4×

Result
12 mg/mL, with a 4× concentration increase.

Interpretation
The recovered fraction is four times as concentrated as the stated starting sample.

Does this estimate centrifuge recovery yield?

No. It calculates the concentration of the recovered fraction. Recovery yield requires a measured or estimated starting amount for comparison.

Can I use micrograms and microliters instead?

Yes, if the mass and volume units are scaled consistently so their ratio represents the concentration unit you want. The displayed labels are mg and mL.

What if the pellet is not completely resuspended?

The computed value may overstate the usable dissolved concentration because the formula assumes the recovered amount is evenly dispersed in the final volume.

Why is starting concentration optional?

It is not needed for the final concentration itself. It is used only to show the fold-change from the starting sample.

How is this different from a dilution calculator?

This calculator starts from recovered mass and final volume. A dilution calculator usually starts from known concentrations and volumes before mixing.