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Dilution Factor Calculator

Calculate the final-to-stock dilution factor and distinguish it from the diluent-to-stock ratio.

By ChemistryCalc•Updated October 28, 2026•References
Your calculationLive results · change any value

Results update as you type. Choose units beside a measurement; changing units converts the current value.

On this pageCalculatorHow to useFormula & methodWorked exampleTwo ratios that should not be confusedConservation and practical measurementFrequently asked questionsRelated calculatorsSources

01 Set up your calculation

  1. Enter the stock aliquot transferred into the new preparation.
  2. Enter the added diluent volume.
  3. Read the total-to-stock factor separately from the diluent-to-stock ratio.

02 The relationship

DF = Vfinal/Vstock = (Vstock + Vdiluent)/Vstock; Cfinal/Cstock = 1/DF.

For the assumptions behind these results, read the explanation below. You can also explore Serial Dilution and Solution Dilution.

WORKED EXAMPLE

Follow the numbers

1 mL of stock plus 9 mL of diluent makes 10 mL total. The dilution factor is 10, the diluent-to-stock ratio is 9, and the final concentration is one tenth of the stock.

03 Two ratios that should not be confused

A tenfold dilution means that the final concentration is one tenth of the stock concentration. Under an additive-volume approximation, one volume of stock is combined with nine volumes of diluent. Adding ten volumes of diluent would instead give an elevenfold dilution.

The calculator shows both ratios explicitly. When recording a preparation, write down the actual stock and final volumes alongside the dilution factor so another person can reconstruct the intended operation.

04 Conservation and practical measurement

The relationship follows from conservation of solute during dilution. It assumes the diluent contains none of the tracked solute and that no solute is lost or created during mixing. The result is independent of which volume unit you choose, provided both values represent the same physical quantities.

Volumes of different liquids are not always additive. For accurate volumetric preparation, take the specified stock aliquot and make the solution up to the required final volume. Small transfer volumes also require equipment suitable for that range; a correct ratio does not remove measurement uncertainty.

Questions from the notebook

Is a dilution factor allowed to be one?

Yes. Zero added diluent leaves the concentration unchanged, so the factor is one.

What does a 1:10 label mean?

Labels can be ambiguous. Here tenfold means one part stock in ten parts final solution.

How do factors combine over multiple steps?

Multiply the factors. Two successive tenfold dilutions produce an overall factor of 100.

References & reading

Our explanations are written for ChemistryCalc. Read how we build and check our tools. These calculations are educational estimates where the underlying model requires assumptions.