Dilution Factor Calculator
Calculate the dilution factor (DF = final volume ÷ aliquot volume) used in serial dilutions and sample preparation. Distinct from C₁V₁ = C₂V₂. For education only.
How to use this tool
- Enter aliquot volume (sample taken) and final volume after dilution in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your dilution factor (df) and the full breakdown beneath it.
The dilution factor is the ratio of final to initial volume: DF = V_final ÷ V_aliquot. A DF of 10 means the sample is 10× more dilute — its concentration is 1/10 of the original.
For serial dilutions, multiply individual DFs together. 3 × 1:10 dilutions give a total DF of 1000.
For education only.
Formula
Dilution Factor (DF) = Final volume (mL) ÷ Aliquot volume (mL)
log10(DF) = log10(Final volume ÷ Aliquot volume)
Concentration fraction = 1 ÷ DF
How it works
The dilution factor expresses how many times a sample has been diluted: take an aliquot of the original sample, add diluent until the total (final) volume is reached, and divide final volume by aliquot volume. This is the standard definition used in microbiology and analytical chemistry serial dilutions. The calculator also reports the base-10 logarithm of the DF (useful for plotting dilution series) and the resulting concentration as a fraction of the original; it assumes perfect mixing and no volume-on-mixing effects.
Worked example
Worked example
- Aliquot volume = 1.0 mL taken from original sample, made up to final volume = 10.0 mL.
- DF = 10.0 mL ÷ 1.0 mL = 10.
- log₁₀(DF) = log₁₀(10) = 1.0.
- Concentration fraction = 1 ÷ 10 = 0.1 (i.e., 10% of the original concentration).
Dilution factor = 10, log₁₀(DF) = 1.0, concentration as fraction of original = 0.1.
Key terms
- Dilution factor (DF)
- The ratio of final solution volume to the volume of sample taken; indicates how many-fold the sample has been diluted.
- Aliquot
- A measured portion of a sample removed for analysis or further dilution.
- Serial dilution
- A stepwise sequence of dilutions where the output of one dilution is used as the input to the next.
- log₁₀(DF)
- The base-10 logarithm of the dilution factor; each unit increase represents a 10-fold increase in dilution.
- Concentration fraction
- The proportion of original concentration remaining after dilution; equal to 1 ÷ DF.
Frequently asked questions
- How is this different from the C₁V₁ dilution calculator?
- C₁V₁ = C₂V₂ calculates concentrations. The dilution factor calculator focuses on the volumetric ratio used in serial dilutions, microbiology, and spectroscopy where you track fold-dilution rather than absolute molarity.
- What is a serial dilution?
- Repeated dilutions where each step uses the previous diluted solution as input. Three 1:10 dilutions gives 1:1000 overall (DF = 1000).