Serial Dilution Calculator and Planner

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.

Calculate serial dilution using	Initial concentration and dilution factor
Stock solution name
Diluent name
Concentration of stock solution	mU / mL
Serial dilution initial concentration	mU / mL
Dilution factor
Final volume of each dilution	mL
Number of dilutions
Number of replicates (optional)

Custom Protocol

The following protocol can be used to prepare a serial dilution of Acetylcholinesterase standard with Assay buffer as the solvent. Values in the table indicate the reagent compositions per dilution.

Dilution	Acetylcholinesterase standard Volume (mL)	Source	Assay buffer Volume (mL)	Concentration (mU / mL)
1	225	from 1 U / mL stock	0	1000
2	75	from dilution 1	150	333.3333
3	75	from dilution 2	150	111.1111
4	75	from dilution 3	150	37.037
5	75	from dilution 4	150	12.3457
6	75	from dilution 5	150	4.1152
7	75	from dilution 6	150	1.3717
Control	0	from Assay buffer	0	0

Pipette 225 mL of 1 U / mL stock into 0 mL of Assay buffer . Mix well before continuing. Avoid generating bubbles.
Pipette 75 mL of dilution 1 (from step 1) into 150 mL of Assay buffer to create dilution 2 . Mix well before continuing. Avoid generating bubbles.
Pipette 75 mL of dilution 2 (from step 2) into 150 mL of Assay buffer to create dilution 3 . Mix well before continuing. Avoid generating bubbles.
Pipette 75 mL of dilution 3 (from step 3) into 150 mL of Assay buffer to create dilution 4 . Mix well before continuing. Avoid generating bubbles.
Pipette 75 mL of dilution 4 (from step 4) into 150 mL of Assay buffer to create dilution 5 . Mix well before continuing. Avoid generating bubbles.
Pipette 75 mL of dilution 5 (from step 5) into 150 mL of Assay buffer to create dilution 6 . Mix well before continuing. Avoid generating bubbles.
Pipette 75 mL of dilution 6 (from step 6) into 150 mL of Assay buffer to create dilution 7 . Mix well before continuing. Avoid generating bubbles. Discard 75 mL from dilution 7 to obtain the correct volume for the final dilution.
Create a blank control using 0 mL of Assay buffer. This should be enough for 2 replicates.
Using the table in the protocol as a guide, pipette -25 mL of each standard into its corresponding well in the experimental microplate. Standards prepared with this protocol should be enough for 2 replicates. Use of a multi-channel pipette is highly recommended.

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References

This online resource may be cited as follows

MLA	"Quest Calculate™ Serial Dilution Calculator and Planner." AAT Bioquest, Inc., 26 Aug. 2026, https://www.aatbio.com/tools/serial-dilution.
APA	AAT Bioquest, Inc. (2026, August 26). Quest Calculate™ Serial Dilution Calculator and Planner. AAT Bioquest. https://www.aatbio.com/tools/serial-dilution.
BibTeX	EndNote	RefMan

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.
Enter the name of the stock solution.
Enter the name of the diluent (solution used to dilute the stock solution).
Enter the stock solution concentration and select the appropriate unit.
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.
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.
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.
Enter the dilution factor for the serial dilution.
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.
Press the calculate button to display results.

Dilution Factor
Calculate dilution factor given initial and final volumes
M1V1 = M2V2
Solve for concentration or volume with a dilution
Serial Dilution
Generates a serial dilution protocol based on dilution factor or concentration range

How to use this tool

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