The qPCR Dilution Dilution Factor Estimator calculates the fold dilution created when a stock aliquot is brought to a larger final volume. It also reports the stock percentage and the amount of diluent implied by the selected volumes.
This is useful for checking qPCR standard-preparation steps, working-solution dilutions, or intermediate dilutions before pipetting. The factor is unitless, so the same calculation works with microliters or milliliters as long as the stock and final volumes use the same unit.
1. Enter the transferred stock volume
Use the aliquot taken from the starting solution.
2. Enter final dilution volume
Use the total volume after diluent has been added, not the amount of diluent alone.
3. Keep volume units consistent
Both values must be expressed in the same unit.
4. Read the fold factor
The final volume divided by the stock aliquot gives the dilution factor.
5. Check the implied diluent
The breakdown subtracts the aliquot from final volume so you can verify the mix plan.
Where:
Assumptions: The calculation assumes an ideal single-step dilution with additive volumes and complete mixing. It does not account for transfer loss or analyte instability.
The final solution has one tenth of the stock concentration after combining 20 µL stock with 180 µL diluent.
The dilution factor is unitless and assumes stock and final volumes use the same unit.
Given:
Calculation:
Dilution factor = 200 ÷ 20 = 10×
Diluent = 200 − 20 = 180 µL
Final concentration = 100% ÷ 10 = 10% of stock
Result:
10× dilution
Interpretation:
The final solution has one tenth of the stock concentration after combining 20 µL stock with 180 µL diluent.
No. Final volume includes both the transferred stock and the added diluent. Entering diluent volume as final volume would understate the true dilution factor.
Under ideal mixing, the final concentration is the starting concentration divided by 10. For example, 100 nM stock becomes 10 nM after a true 10× dilution.
For multiple steps, multiply the dilution factors of each step to get the overall factor. A 10× step followed by another 10× step gives a 100× overall dilution.
The factor is 1×, the implied diluent is zero, and the concentration remains 100% of stock. That is effectively no dilution.
Pipetting error, residual liquid, incomplete mixing, adsorption, degradation, and stock uncertainty can cause the realized concentration to differ from the nominal dilution calculation.