Serial dilution calculator

For many quantification assays, a set of standards must be run alongside test samples in order to calibrate an experiment properly. These standards are used to create what is known as a calibration curve, or standard curve. From this curve, the quantity of target in a sample can be calculated.

Standards for the calibration curve are typically chosen such that they span the linearity of a given assay. This represents the range of quantities over which response values are directly proportional to changes in the target of interest. For many quantification assays, the linearity range is logarithmic in nature. Thus, when creating standards for a given assay, it is often necessary to prepare the standards using a serial dilution.

A serial dilution is a sequence of dilutions created using the same dilution factor. For instance, creating a two-fold dilution with a starting concentration of 10 µM yields the following concentrations: 10 µM, 5 µM, 2.5 µM, 1.25 µM, etc.

The tool below can be used to create a protocol for preparing a serial dilution from a stock solution.

How to use this tool:

1. Select the method for calculating the serial dilution. Serial dilutions can be calculated either using a starting concentration and dilution factor OR a concentration range.

2. Enter the name of the stock solution.

3. Enter the name of the diluent (solution used to dilute the stock solution).

4. Enter the stock solution concentration and select the appropriate unit.

5. Enter the desired initial concentration. In a microplate format, this represents the desired concentration of the first well. For a series of test tubes, this is the desired concentration of the first test tube. Select the appropriate unit. Please note that the initial concentration value cannot exceed the concentration of the stock solution. The initial concentration can, however, be the same as the stock solution concentration.

5. If the unit of the stock solution is different than that of the initial concentration, the molar mass of the stock solution will be required.

6. Enter the desired final volume for the serial dilution. Please note that each serial dilution will have the same final volume. In a 96-well microplate format, the maximum volume for a single well is typically 300 µL. Select the appropriate unit. It is recommended to include excessive dilution volume to account for loss that may occur during pipetting.

7. Enter the dilution factor for the serial dilution.

8. Enter the number of times the serial dilution needs to be performed. For a 96-well microplate format, this number is typically 7 (if using a single column) or 11 if using a single row. The final well is usually filled with diluent to serve as a negative control.

9. Press the calculate button to display results.

Calculate serial dilution using
Stock solution name
Diluent name
Concentration of stock solution
Serial dilution initial concentration
Dilution factor
Final volume for each dilution
Number of dilutions